![Thumbnail: [Volume 37, 1904 page 318]](/journals/rsnz/images/rsnz_37/thumbnails/rsnz_37_00_0344_0318_ac_02.gif)
Atagema, Gray [p. 39].
Gray, fig. iv., 1850, p. 104; Guide, i., 1857, p. 209.
Form and internal structure as in an Archidorid. The back carries a median keel. As was so frequently the case, Gray erected a new genus (Atagema) on a drawing (by Quoy and Gaimard) of an animal presenting a somewhat peculiar appear-ance.
The animal described below belongs to the Archidorididae: it has the general body-form of the family, with granulated
![Thumbnail: [Volume 37, 1904 page 319]](/journals/rsnz/images/rsnz_37/thumbnails/rsnz_37_00_0345_0319_ac_02.gif)
back and a widish mantle-flap, with tri- or quadri-pinnate gills, small tentacles, and rather stout foot. The oral disc (Lippen-scheibe) is unarmed; the radula has a narrow naked rhachis, and numerous hook-like plates. Within this large family of Dorids it approaches most nearly the genus Archidoris. It shows well the short finger-shaped tentacles and the relatively small number of gills. The penis and vagina are both unarmed. Apparently the only peculiarity about the animal is the dorsal keel, and it-must for the present remain doubtful whether Gray was justified in founding a new genus on this character alone.
Atagema carinata (Q. and G.). Doris carinata, Q. and G., Voy. de 1'Astrolabe, ii., p. 254, pl. 16., figs. 14–16. Atagema carinata, Gray, fig. iv., p. 104. [Bergh figures it] pl. iii., fig. 8–11.]
An individual of this species lies before me, obtained by Dr. Benham from Dusky Sound, at the south-west corner of the South Island. The living animal is pure-white. The sketch made by Benham (fig. 8) is from an individual preserved in formol.
[I exhibited a specimen of this Dorid at a meeting of the Otago Institute in 1898,* and drew attention to the fact that it was the “D. carinata” of Quoy and Gaimard. Since sending the specimen to Dr. Bergh, I have received from Mr. R. Henry, at Dusky Sound, others of a larger size—viz'., length, 8–9 cm.; breadth, 6–7 cm.; height, 3.3 cm.
The specimen in alcohol is much arched, contracted, and hardened; it had been broken. It is now yellowish-white in colour.
[Dimensions (p. 40).] The length was [in an extended condition] probably 5–6 cm., with a breadth of 4 cm., and a height 2.5 cm. The dorsal keel has at its greatest length a breadth of 5–7 mm.; it is narrower in front and behind, while posteriorly to the protuberance its height is 5 mm. The width of the mantle-flap is at least 12 mm., and its thickness at the base is 7 mm.; the height of the rhinophore-sheath is 4 mm., and of the branchial papilla 4 mm.; the breadth of the foot is 22 mm., and of the margin of the foot 4 mm.
[Externals.] The consistency is leathery; the back is quite finely shagreened. The form is oval, with a somewhat arched back; the mantle-flap broad, and the foot projecting all round. The back carries a great median keel, which commences anteriorly between the rhinophores. It is at first somewhat low and narrow, then becomes thicker, and behind the middle
[Footnote] *See Trans. N.Z. Inst., xxxi., p. 743.
![Thumbnail: [Volume 37, 1904 page 320]](/journals/rsnz/images/rsnz_37/thumbnails/rsnz_37_00_0346_0320_ac_02.gif)
of its extent becomes elevated into a blunt point; thence it continues as a much narrower ridge to the gills. The projecting rhinophore-sheath has a circular aperture. The club of the retracted rhinophore is 4 mm. high, is closely foliated, and terminates in a small papilla. The branchial cone consists of four converging lappets (5 mm. high) with rounded ends. The deeply sunk gill is formed of six* tripinnate members, 7 mm. high, of which the two anterior are the larger. The relatively thin anal papilla, which is 3 mm. high, is curved forward, and subcentral in position. The retracted tentacle is 2 mm. high, short, finger-shaped with a groove on the underside. The foot is stout and broad, rounded in front, with a marginal furrow; the tail is relatively short.
[Remarks (p. 41).] The animal here described appears really to represent the Doris carinata of Quoy and Gaimard, which since the expedition of the “Astrolabe” in 1828 has not been met with. The French zoologists obtained the animal in New Zealand [in the estuary of the Thames, Hauraki Gulf]. The size (tres petite espece) of the individuals examined by them appears, however, to have been very much less [than the specimens now under consideration], the colour yellowish-white, and the number of gills only four.
[In view of the interest of this species I append figures of a specimen, natural size, in side view and from below (see Plate XVIII.).]
[Footnote] * In specimens in my possession I find the branchial cone to consist of five lappets or valves, and the gill consists of five members (Benham).