5^8 GASTROPODA. [Opisthobranchia, 



Length, 9 mm. ; height, 3 mm. ; breadth, 3 mm. (largest alcohol 

 specimen). 



The internal organs are described by Bergh. On the labial cuticle 

 is a ring (apparently consisting of two semicircles which nearly meet) 

 composed of small rods with tips sometimes entire and sometimes 

 divided. The formula of the radula is 31 x 2 + + 2. The teeth 

 are transparent. The inner tooth is large, and bears at least 20 

 denticles. The outer tooth is a small plate, bearing in most cases 

 a single low but distinct cusp. 



Co-type in my collection. 



Hob. Near Akaroa Harbour, in about 8 fathoms (H. S.). 



Genus 2. ACANTHODOKIS, Gray, 1850. 



Acanthodoris, Gray, Figs, of Moll. Anim., iv, 1850, 103. Type : A. pilosa, 

 Miiller. 



Body depressed, oval, convex ; mantle moderate, covered with 

 soft papillae ; oral tentacles united in a veil, with free flattened lateral 

 ends ; rhinophores retractile within denticulated sheaths, their clubs 

 beautifully laminated. Branchia formed of tripinnate plumes arranged 

 in a circle. Jaws composed of small denticles or hooks. Radula 

 without a central tooth, a large unciform lateral and several small 

 marginal teeth. 



Distribution. North Atlantic, North Pacific, New Zealand, Tas- 

 mania. The genus is characteristic of the colder seas, and is not 

 recorded from the tropics. 



KEY TO SPECIES. 



A. Mantle with small, scattered, soft, conical, and pointed tubercles . . globosa. 



B. Mantle with large, linear, soft papillae, especially numerous at the 



sides and around the branchiae . . . . . . . . molicellcii 



1. Acanthodoris globosa, Abraham, 1877. 



Acanthodoris globosa, Abrah., P.Z.S., 1877, 262, pi. 30, f. 5-9 ; M.N.Z.M., 

 128 ; Eliot, P. Mai. S., vii, 329, 350. 



Body ovate, broad, very convex and inflated. Mantle membranous 

 on the back and sides, reaching down over the foot, except perhaps 

 quite behind, and bearing scattered, soft, conical, pointed tubercles, 

 which are more numerous towards the border. The integuments are 

 very thin and the dorsal tubercles sparsely scattered. The rhinophores 

 are apparently rather short and slender, laterally flattened, and re- 

 tractile within the sheaths, of which 2 of the marginal processes are 

 larger than the others. Branchiae 7, bi-(? tri-)pinnate, non-retractile, 

 situated around the anus, far back and low down. Oral veil short, 

 very wavy, the sides prolonged, free and flattened. Foot broad, 

 truncate in front, with a very indistinct transverse groove ; it is 

 rounded behind, and the margin all around is very wavy. Colour 

 (in spirit) transparent white, with a blue coloration on the back and 



