Archidoris, Bergh, 1892.†
A. violacea, Bergh, n. sp. [p. 31]. PI. ii., figs. 36, 37; p1. iii., fig. 1.
This form was frequently obtained by Benham at a depth of 30–40 fathoms at various stations between Otago Peninsula and Oamaru. [I have obtained it in bucket-loads from fish-trawlers.] The living animal attains a length of over 6 in., and a breadth of 2½ in. The colour is a fine violet, with orange-coloured “tentacles” and foot.
[Dimensions.] The single specimen [that I sent him before I had ascertained its great abundance], when in alcohol, has a length of 4 cm.; breadth, 2.5 cm.; height, 1.7 cm. The mantle-edge is 5 mm. broad; the foot is 1.7 cm. broad, its margin 3.5 cm. broad; the tail is 5 cm. long. The height of the rhino-phore-sheath is 1 mm., and of the rhinophore itself 7 mm. The diameter of the entirely protruded gill is 1 cm.; length of individual branches, 5 mm. Height of anal papilla, 1 mm.
[I am ignorant as to the value or otherwise of these measurements for identification. It seems to me that many of them depend upon the mode of preservation. If slowly killed, with the various parts fully extended—as can be done by means of weak alcohol, cocaine, and so forth—the measurements will be very different from those taken on an individual of the same size killed by plunging into corrosive sublimate or strong alcohol. However, I give these details as they appear in the memoir.]
The colour of the preserved specimen is throughout yellowish-white. The back is covered all over with relatively closely set slightly protuberant rounded tubercles of whitish colour, and with a diameter of 4 mm. [These tubercles in life are violet.]
[Externals (p. 32).] The form is a longish oval, the back fairly arched. The tubercles towards the margin of the back are smaller and more crowded. The rhinophores are closely foliated. The gills, situated far back, are formed of eight tri-pinnate members, of which the hindmost are slightly smaller.
[Footnote] † It may be as well to state that this name replaces the term Doris, which is no longer used as a molluscan genus.
The anal papilla is nearly in the centre of the branchial crown. The mantle-flap* is of nearly the same breadth throughout; its under-surface smooth. The foot is rounded in front, with well-defined marginal groove; the margin is not very narrow; the tail short.
[Remarks (p. 33).] From its coloration this form probably represents a new species; possibly it is identical with one or other of the “species” recently described from the Pacific Ocean.†
[I confess I do not understand the above remark. If it is merely its coloration that distinguishes it, it seems scarcely probable that that would justify the formation of a new species. I may note that Sir G. Eliot, in his account of the “Nudibranchs of East Africa and Zanzibar,”‡ suggests that his A. africana may be identical with this species, and A. umia with A. nanntla. It is rather odd that Bergh does not refer to Abraham's paper in the Proc. Zool. Soc. 1877, in which several opisthobranchs from our coasts are described and figured. It is evident that all our nudibranchs require working over carefully, for it seems likely that the littoral forms have received more than one name. It will be seen, later, that in the case of other species there is the same hesitation or doubt as to its novelty or otherwise. Unfortunately, the valuable memoirs that Bergh has been publishing for some years past are very much too expensive for individual workers to purchase, and none of our libraries possess the work.]
A. nannula, Bergh, n. sp. [p. 33], p1. iii., fig. 2.
Of this form Benham has forwarded seven individuals, obtained at Port Chalmers, Otago Harbour. [I collected some dozens of this bright little species when the s.s. “Ringarooma” was in dry dock, after being at moorings for about a year in Deborah Bay, amongst the seaweeds, Bryozoa, sponges, &c., adhering to the bottom of the ship. I collected a considerable number of interesting animals, amongst others the Goniodoris castanea, referred to above.]
[Colour.] During life they are light—orange—coloured. In alcohol the seven individuals agree pretty well in colour, size, and form. They were entirely yellowish-white.
[Dimensions.] The length averages about 18mm., with a breadth up to 14mm., and a height of 3 mm.; the breadth of
[Footnote] * By this I translate “Mantelgebram.”
[Footnote] † R. Bergh: Chall. Repr., p. 85; Die Opisthobr., Alaska, 1894, p. 159 (A. kerguelensis); Die Opisthob. d. Sammulung Plate, Zool. Jahrb, Suppl., iv., 3, 1898, p. 501 (A. rubescens: A. (?) incerta); Ergebn. Reise. n.d. Pacific (Schauinsland), Zool. Jahrb., xiii., 3, 1900, p. 222 (A. nyctea).
[Footnote] ‡P.Z.S., 1904.
the mantle-flap is about 14mm. [sic.: probably a misprint]. The height of the gills is 4.5 mm.; breadth of the foot, 7 mm.
[Externals.] Form as usual. The back is entirely covered with almost hemispherical papillae, not very variable in size, but somewhat smaller at the mantle-edge. The club of the rhino-phore is much foliated, the foliae stiffened in the usual way with long spicules. The branchial region is in all the individuals much everted, and surrounded by the narrow lip of the distended gill-opening (which measures 6 mm. in diameter). The gill is formed of five to seven tripinnate members: the upright anal papilla completes the branchial circle posteriorly. The under-surface of the mantle-edge is smooth; the tentacles appear to be shortly conical; the foot is fairly broad, rounded in front, with a short tail.
[Remarks (p. 34).] This form is undoubtedly an Archidoris, but whether it represents a distinct species must remain for the present undecided.
Archidoris, sp. [p. 34].
The single specimen obtained by Benham at Kaikoura, on the east coast of the South Island, was, in life, pale-orange in colour.
[Colour.] The specimen in alcohol was much hardened, broken, somewhat contracted, and uniformly light-yellowish.
[Dimensions.] Length, 23 mm.; breadth, 16 mm.; height, 10 mm. Breadth of mantle-flap, 3 mm.; of the foot, 13 mm. The height of the rhinophore, 2 mm.; the diameter of the circular branchial aperture is 4 mm.; height of the gill, 3 mm.
The animal was somewhat hard and stiffened; the back fairly smooth, but finely granulated towards the margins; the rhinophores, lying far forward, has its club much foliated. The foot is large; its margin not broad; the tail short.
[Remarks (p. 35).] This form is probably identical with one of the recently described species of the genus.
Homoiodoris, Bergh, 1881.
Hitherto only one species of this genus, H. japonica, has been described, and this from the South Japan Sea.
H. novae-zealandiae, Bergh, n. sp. [p. 35], p1. iii., figs. 3–7.
Of this form five individuals were received from Mr. H. Suter, who collected them at Port Chalmers.
[Dimensions.] The specimens preserved in alcohol had a length varying from 12–20 mm. In the largest individual the breadth of the body is 13 mm.; the height, 7 mm.; the width of the mantle-flap is 3.5 mm.; that of the border of the foot is 3 mm.: the length of foot is 16 mm.; its breadth, 7 mm.;
the tail, 2 mm. The height of the (retracted) rhinophore is 2 mm.; length of tentacle, 1 mm.; height of the gill, 3 mm.; diameter of the branchial star, 7 mm.
[Colour.] The colour of the back is whitish or faintly yellowish white; the tubercles white; the head and foot inclining to yellowish; the clubs of the rhinophore and the gill are chrome-yellow. One individual had the under-surface of the mantle-flap spotted with violet-grey.
[Externals.] In consistency the animal is somewhat stiff. The form as in other Archidorids. The back is covered pretty closely with tubercles of dissimilar size, somewhat flattened on the apex (at least in the case of the larger ones): they attain a height and diameter of about 0.5 mm. Similar tubercles are also present at the edge of the rhinophore-pits and gill-aperture. [p. 36] The club of the rhinophore bears about 20 foliae; the branchial aperture is transversely oval; the gills number 5 or 6; the cylindrical anal papilla is relatively high (1 mm.). The under-surface of the mantle-flap is smooth; the sides of the body angular. The foot has a distinct groove at its anterior edge; the tail is short; the tentacles are short, thick, with grooves on the under-side.
[Remarks (p. 37).] Whether this form belongs to the genus Homoiodoris remains for the present undecided, since the most essential character—the armature of the vagina—was not established owing to the condition of preservation. If this armature noted [in the text] belongs to the sperm-duct, either a new genus will have to be formed, or it belongs to the genus Artachae,* in which, however, no prostate is developed. The vestibular glands and sac existing in the present species are absent from Homoiodoris and from Artachaea. From the hitherto known species of Homoiodoris, as well as of Artachaea, this new form is, however, specifically distinct, as is evident from the comparison of the radula—the innermost as well as the outermost teeth being quite unlike those of other species.
[Footnote] * See Bergh, “System d. Nudibranch: Gasteropoda,” 1892, p. 1093.