Art. XIV.—Notes on Delphinus forsteri.
[Read before the Wellington Philosophical Society, 22nd September, 1873.]
In March last a specimen of Delphinus forsteri, which was cast up on the beach at Lyall Bay, gave me, for the first time, an opportunity of observing its external characters and of having a sketch made, which does not, however, differ sufficiently from that copied last year after Forster to make it worth reproduction (Vol. V., Pl. 3). Unfortunately the colouring had faded, so that the whole skin was of a dark tint, and the spots on the fins, mentioned by Forster, could not be distinguished. The skull, however, since prepared agrees exactly with that which I have already described as belonging to Forster's Dolphin, although the drawing given in the last volume of Transactions, of the first skull I had, does not show the full width behind the notch.
The following are the notes I made of its characters:—
Beak sharply defined above by a frontal groove. Forehead very curved. Fore part of the body fullest. Hind part of the body much compressed vertically, being 6 inches in advance of the tail lobes, 6 inches high, and only 2 inches thick. Tail strongly keeled, both above and below; notched. Lower jaw longest. Length of pectoral equal to gape, and greater than height of the dorsal.
|Snout, upper surface||0||5.5|
|Blow-hole from tip of beak||1||1.5|
|Commencement of dorsal at||3||1.5|
|Base of dorsal—length||1||0|
|Height of dorsal (posterior edge being nearly vertical)||0||8.5|
|Insertion of pectoral from beak||1||5.5|
|Length of pectoral||1||0|
|Width " (constricted at base)||0||4|
|Generative organs, behind posterior vertical of pectoral||0||9|
|Width of tail-lobes from tip to tip||1||6|
The complete skeleton of this specimen is being prepared, and will be the subject of a further communication. I may say, for the present, that the intermaxillaries, as in all the skulls of this dolphin I have previously seen, are united to form a bony tube for fully one-third of their length.