B. Family Palapterygidæ.
a. Genus Palapteryx.
Metatarsus very short and broad, with hallux and hind toe; distal trochleæ
remarkably broad and divergent, tibia with both extremities largely developed and standing inward, so as to give the skeleton a bow-legged appearance; pelvis very broad and like the bones of the leg, and the rest of a truly pachydermal character; bill very obtuse and rounded at the tip; sternum flattened, broader than long, with a strong costal process, lateral processes standing at a higher angle than in any of the Dinornithidæ; no coracoid depressions in aged specimens; no bony scapulo-coracoid, two intercostals only.
b. Genus Euryapteryx *
Metatarsus short and broad, but not so pachydermal as the former, with a hallux and hind toe; tibia straighter, and without the extremities so enlarged as in Palapteryx; sternum longer than broad, more concave than the former genus, without coracoid depressions, but with strong and long costal processes, mesial portion anl process comparatively longer than in all the former subdivisions, no bony scapulo-coracoid, beak not so obtuse as in the former.
In the preceding list I have only entered those well-defined species of which we possess ample material for comparison and generalization, leaving several others, of which we obtained only portions, for a future notice; but amongst them I may at least allude to one species which appears to approach the Emu of Australia in its general characteristics. I had also the intention to add some notes on the crania of the different genera, but fear that it would make this address too long were I to give them here.
However, before proceeding there is one point to which I wish to draw your attention, namely, to the existence or absence of a bony scapulo-coracoid.
In the genus Dinornis we find deep and well-defined coracoid depressions in the anterior border of the sternum of each species; and the excavations have furnished us with a series of scapulo-coracoids which fit exactly into those depressions. Moreover, these small and peculiar bones, by their form and size, agree also in other respects well with the different species enumerated. However, when we examine the sternums of the genus Palapteryx, and principally that of Palapteryx elephantopus, we find some with well-marked depressions, others with only faint ones; whilst there are others, belonging apparently to aged birds, where there is not the least appearance of them.
Again, we possess a few sternums in which a depression exists on the one side, whilst it is missing on the other; so that we are compelled to conclude that no bony scapulo-coracoid could articulate with them. Moreover,
[Footnote] * From euryx, broad; and apteryx, without wings.
we have never found any scapulo-coracoids of a different form from those articulating with the five species of Dinornis, and, as we have obtained a number of the most minute bones of the smallest species, it would be difficult to conceive that a bone of such considerable size should altogether have escaped, the more so as so many specimens of Palapteryx were excavated. And, although this is only negative evidence, it is so strong that there is not the least doubt in my mind of the non-existence of a bony scapulo-coracoid. The same might, indeed, have existed in a cartilaginous form, attached to the sternum by cartilage, but of this we have no evidence. I am well aware that on physiological grounds the presence of that bone seems to be indispensable for the mechanism of respiration in birds, as Professor Owen has shown from his dissection of Apteryx, and he has lately again called my attention to the fact (letter to me, dated British Museum, August 5, 1873); but, with the data at present before us, I cannot alter my views, the more so as I do not deny that such a process might have existed as cartilage.
It will be seen from the subdivisions given above that I have not used the term Dinornis giganteus, as there seems to be a specific difference between the species of that name from the northern island, to which that term was first given by Professor Owen, and the largest bird of this island. In this I have followed Professor Owen, who has proposed the specific term of Dinornis maximus for the latter, which appears to have been altogether of more gigantic proportions than the North Island bird. I was once under the impression that a specific difference could be traced between the largest skeletons known, for which the above term maximus was first used by Professor Owen, and the somewhat smaller skeletons, for which for some time the designation giganteus was retained by me; but, after a careful examination of a number of skeletons, there remains not the least doubt in my mind that they all belong to the same species, with a gradual decrease of size and robustness. And even assuming that the largest skeletons belonged to the female birds—a similar considerable difference in size being also constant with the different species of Apteryx—there are so many intermediate forms that even the supposed line of division between both sexes is exceedingly difficult to draw.
Moreover, and this is peculiar to Dinornis maximus, there are scarcely two skeletons entirely alike; there are some which have a remarkably long metatarsus, whilst the other leg bones do not (at least at the same rate) increase in size; others are much stouter for their height. Altogether we might trace the same peculiarity in size and form as in a series of human skeletons selected at random.
The same is the case with the skeletons of the immature birds of this species, of which we possess portions from the chick to the full-grown giant bird, where the tarsal epiphysis is not yet so closely united with the metatarsus
but that the line of junction is still visible, where also a similar variety of form can be traced.
The difference in size between Dinornis maximus and Dinornis robustus, the next in size, is very marked and constant. Of the latter we obtained a series of two sizes, of which the largest might be assigned to the female.
Between Dinornis robustus, ingens, gracilis, and struthioides, besides their well-defined specific characters, there are also distinct breaks; each species possessing at the same time two constant sizes.
Of Meionornis casuarinus a series of four clearly-defined sizes are in our possession, so that we might conclude that we have two closely-allied species before us, of which the two largest sizes represent male and female of the one, and the two smaller male and female of the other. A considerable difference in size occurs between the smallest species of Meionornis casuarinus and the largest species of M. didiformis. In the latter we can distinguish also four sizes with a gradation similar to that observed in the former, so that I am led to believe that this species, like M. casuarinus, consists of two sub-species.
If we compare two skeletons of Apteryx australis, male and female, and two of Apteryx oweni, male and female, with each other, a similar distinct gradation is observable.
Palapteryx elephantopus has also four well-distinguishable subdivisions, of which the largest size is the most conspicuous and best marked, so that the suggestion ventured concerning two sub-species belonging to Meionornis casuarinus and didiformis applies equally to this remarkable extinct bird.
The division between this and the next species Palapteryx crassus is well marked, consisting, moreover, of two constantly-maintained sizes.
Euryapteryx gravis and rheides, which can easily be distinguished at a glance from each other, not only by their size but by their anatomical characteristics, consist each of two sizes only, to be attributed, as I suppose, likewise to difference of sex.
Amongst other species of extinct birds, of which the Glenmark turbary deposits have yielded remains, there is, first, the huge diurnal bird of prey which I described under the specific term of Harpagornis moorei. Another remarkable species is a ralline form of gigantic size, Aptornis, of which we obtained sufficient material for articulation, and which is closely allied to Ocydromus, the woodhen.
The remains of Cnemiornis, a gigantic goose, as first pointed out by Dr. Hector, have hitherto been very scarce, so that we possess only a few bones of it. It is remarkable that the excavations undertaken during a number of years did not yield a single bone of Notornis, which, therefore, either did not inhabit this part of the country, or was of extremely rare occurrence.
Of other species we obtained bones of Apteryx, Stringops, Ocydromus,
Himantopus, Botaurus, HŒmatopus, several species of ducks, and of a number of still smaller birds which cannot be distinguished from bones belonging to recent species. The remarkable fringed lizard, Hatteria punctata, was also an inhabitant of this island, as several bones belonging to it were found with the Moa bones.
Professor Owen having described at some length, in several of his memoirs on Dinornis, the affinities our struthious birds bear to those of other countries, pointing out at the same time the peculiarities in which they vary from them, it would have been unnecessary for me to add anything to the subject had not an attempt been lately made by Professor Alphonse Milne-Edwards, in Paris, to show, from a comparison of the remains of the extinct ornithic fauna exhumed in Madagascar, Mauritius, and Rodriguez, that in some distant ages New Zealand formed a portion of a large continent, or of a group of more or less extensive islands in the Southern Hemisphere, which at one time were in some way connected with each other. He thinks that additional confirmation can be obtained from the ascertained occurrence of different Ocydromidæ, such as the Aphanapteryx and the Miserythrus leguati, which latter he informs me (letter to me, dated “Jardin des Plantes, Paris, Aug. 3, 1873”) bears close resemblance to our common woodhen (Ocydromus australis).
However enticing the tracing of close affinities must be to the naturalist-philosopher, I believe that it would be rather rash to conclude the connection of two such distant insular groups from a few forms of birds only. Leaving the general question alone for the present, to which I shall return shortly, it is impossible for me to conceive that two countries, which in all other respects have such a dissimilar and distinctive flora and fauna, could have been united in any way without having left other living proofs of such connection in their present endemic organic life, not to speak of fossil remains.
We know that Madagascar is a zoological sub-province of South Africa (Ethiopian region), but having a fauna so peculiar that it must, according to Sir Charles Lyell, have been separated from Africa probably since the upper miocene era. New Zealand, on the other hand, although it may have been formerly of larger extent, has never been more than an oceanic continental island from a zoological point of view, a theory first propounded by Darwin and Wallace, and with which I fully agree. It would be rather a difficult task to prove, upon such slender grounds as the presence of a few species of Struthious and Ralline birds will afford, that both countries could possibly have been connected. Moreover, the difference in the anatomical structure of the three Madagascar species of æpyornis and of the New Zealand Dinornithidæ—using this latter term in a general sense—is so enormous that I fail to see how they possibly could prove that connection in any way.
I cannot agree with Professor Alphonse Milne-Edwards, that the æpyornis stands nearer to Dinornis than to the Ostriches, Cassowaries, and Emus, except that the fossil bones of Madagascar and New Zealand have a more pachydermal type than the recent species named. But I may point out that the fossil Dromornis australis of Australia shows similar characteristics, and I am sure if fossil remains of struthious birds in beds of post-pliocene age were discovered in Africa, America, and Asia, that they would exhibit a similar pachydermal character.
Judging from Professor Milne-Edwards' own excellent memoirs on æpyornis, and the fine casts of the unique fossil bones in the Paris Museum, which he was good enough to send to the Canterbury Museum, I am unable to trace their relationship with our Dinornithidæ. It appears to me that the Madagascar species are separated from the former by many fundamental differences, such as (to point out only a few) the pneumatic foramen in the femur and the straightness of the trochleæ of the metatarsus. And, although I am convinced that the struthious character of æpyornis has sufficiently been proved by the eminent Paris comparative anatomist, I can easily understand that there was at first some show of reason for placing it amongst the sarcoramphous vultures, as has been done by Professor Bianconi.
However, speaking of the principle itself, I wish to point out that if we were to decide, from a few isolated species in two distant countries which show some or even a close resemblance to each other, that these countries must have once been connected in some way, we should in many instances form erroneous conclusions. We might as well say that, because there are struthious birds in Australia, the Malay Archipelago, Africa, America, and Asia, all these countries must have been connected with New Zealand; or because Marsupial remains have been found in secondary rocks in Europe, and several species of opossums are living in America, these countries had also been united with Australia.
Speaking from a general point of view, I wish to add that the attempts to trace the geographical relations of a fauna and flora of a country can easily be exaggerated, and thus a theory be ridden to death which otherwise would be very useful. Moreover, an unfortunate country, such as New Zealand, of which a good number of the species of its fauna and flora show great resemblance to other species from distant countries, has to be dipped down and brought up again a great many times, in order to establish connections in various directions, so that a bird or fish, a shell, insect, or centipede, might cross from the one to the other without allowing, moreover, any other species from the same country to pass. Besides, the geological record of these islands at present at our disposal does not warrant us in assuming such repeated changes in the level of the land.
Can the explanation of such close specific resemblance not be found, in many instances at least, in the adoption of more simple natural causes, such as the transport by icebergs or on floating islands, by birds, etc., and of which Sir Charles Lyell, in his great work, the “Principles of Geology,” gives many striking instances? However, where the theory of land connection is not admissible, and where also others, which have hitherto been applied, fail, might we not assume that similar climatic and other physical conditions could produce similar specific characters under the great law of evolution? It is a most difficult problem to say what constitutes a species, and therefore might it not be safer to believe, until the impossibility of such an hypothesis has been demonstrated satisfactorily, that there exists a similitude as well as an identity of species under certain given conditions?
In one word, might we not throw out the conjecture that in two more or less distant countries, which never were directly united, some forms of organic life can and do exist, which show what to us appear identical specific characters, because the cause or causes of their evolution were identical or nearly identical, and thus a considerable number of supposed changes in the level of many countries, of which we do not find geological records, can be dispensed with? It is true that instances to be explained by the migration or accident theories are of more frequent occurrence and more easily proved, but I think it would be just as interesting, where these cannot be admitted, to trace in all its bearings the similitude of species in distant countries. This view would at least open up a field of fresh research, and afford a new illustration and confirmation of the great theory of evolution.
Some discussion then took place on the address.
Mr. Maskell stated that he had undertaken on behalf of the society to write a history of Canterbury, but he had since come to the determination to give up the task, inasmuch as the Province was yet too young to permit of anything but a history of dry details being written.