.Don'*.] GASTROPODA. 561 



margin. The labial disc merely clothed by a simple cuticle. The 

 radula without central tooth, with numerous hook-shaped plates on 

 either side from the middle. The large ventricle free. Verge and 

 vagina unarmed. 



Only a small number of species are known. The genus is probably 

 cosmopolitan, but most abundant in temperate seas. 



KEY TO SPECIES. 



A. Back entirely covered with hemispherical papillae of various 



size ; gill formed of 5-7 tripinnate members, the anal 



papilla completing the branchial circle posteriorly . . nanula. 



B. Back with large tubercles, smaller and more crowded towards 



the margin ; gill formed of 8 tripinnate members, the anal 



papilla nearly central . . . . . . . . violacea. 



C'. Back with large rounded tubercles, with small white tuber- 

 cular spots between them ; gill formed of 7 tri- sometimes 

 quadri-pinnate members, the anal papilla subcentral . . wellmgtmensis. 



1. Doris nanula, Bergh, 1904. 



Archidoris nanula, Bergh, Semper's Reise Philipp., Malac. Unters., vi, 1904, 

 33, pi. 3, f. 2 ; Benham, T.N.Z.I., xxxvii, 316 ; Eliot, P. Mai. S., vii, 328. 



Form as usual. The back entirely covered with almost hemi- 

 spherical papillae, not very variable in size, but somewhat smaller at 

 the mantle-edge. The club of the rhinophore is much foliated, the 

 foliee 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 5 to 7 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. Colour : During life the animals are light-orange-coloured ; 

 in alcohol they are entirely yellowish-white. 



Length, about 18 mm. ; breadth, up to 14 mm. ; height, 3 mm. 

 Height of the gills, 4-5 mm. ; breadth of the foot, 7 mm. 



Hab. Collected by Professor Benham from the hull of the s.s. 

 " Eiugarooma," when in dry dock at Port Chalmers, after being at 

 moorings for about a year in Deborah Bay. 



Remarks. This form is undoubtedly an Archidoris, but whether it 

 represents a distinct species must remain for the present undecided 

 (Bergh). Perhaps identical with an East African form (Eliot). 



2. Doris violacea, Bergh, 1904. 



Archidoris violacea, Bergh, Semper's Reise Philipp., Malac. Unters., vi, 1904, 

 31, pi. 2, f. 36, 37 ; pi. 3, f. 1 : Benham, T.N.Z.I., xxxvii, 315 : Eliot, 

 P. Mai. S., vii, 328. 



Form of the animal 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 



