Benham. — Nudibranch Molluscs from Neiv Zealand. 315- 



is distinct from T. challengeriana and T. dioncedea, while from 

 T. exsulans it differs in the buccal veil and the number of teeth 

 at the radula.* 



NUDIBRANCHIATA HOLO H EP ATIC A. 



DOPJDIDiE CRYPTOBRANCHIAT.E. 



Fam. ARCHIDORIDL^. 



Archidoris, Bergh, 1892. f 



A. violacea, Bergh, n. sp. [p. 31]. PL ii., figs. 36, 37; pi. hi., 

 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 2| 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 - 5cm. ; height, 1*7 cm. The mantle- 

 edge is 5mm. broad; the foot is TTcm. 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 indi- 

 vidual branches, 5 mm. Height of anal papilla, 1 mm. 



[I am ignorant as to the value or otherwise of these measure- 

 ments 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. 



* Bergh, Opisthobranchen. Rep. of " Albatross," Bull. Mus. Comp. 

 Zool., Harvard, xxv., 1894, p. 150. 



t It may be as well to state that this name replaces the term Doris, 

 which is no longer used as a molluscan genus. 



