NUDIBRANCHS OF THE VANCOUVER REGION I7I 



ventral portion consists of a thickened curved piece of chitin passing 

 backwards to a point and anteriorly as a forked extremity. On the out- 

 side and passing dorsally at right angles to the other are two curved 

 somewhat leaf shaped plates wide;- at the base and narrowing off to a 

 point each composed of a large number of small triangular denticles. 

 The genital aperture is high up on the right side of the body under the 

 mantle just behind the level of the rhinophores. The penis is sub conical 

 and armed with minute hooks. 



This species was first described from Monterey by MacFarland (10, 

 11) who has given a good description of its internal anatomy. 



Habiat. — ^The species was obtained on the rocks of Jesse Island in 

 April and May 1919, and from other places not recorded. MacFarland 

 reports that it is rare and that only four specimens have been obtained. 

 They are also rare here but I was able to get three living specimens apart 

 from those collected previously some of which also come from Jesse 

 Island. 



AcANTHODORis BRUNNEA (MacFarland). 



Acanthodoris brimnea MacFarland, Proc. Biol. Soc, Washington, Vol. 

 XVIII, 1905, p. 52. 



Body. — The body is somewhat oval in outline but markedly broader 

 in the front than at the hinder end. It is also not so high as in other 

 Acanthodorids. The mantle is wide and thick and covers the foot every- 

 where save at the posterior end in locomotion. The whole of the dorsal 

 surface is covered with papillae apparently of two sizes high and low 

 irregularly arranged. 



Colour. — ^The dorsum is a brown colour covered with specks of deep 

 brown almost black. The rhinophores are also of this deeper colour. 

 The front edge of the mantle, the branchiae and the tip of the cla\'T.is of 

 the rhinophore are yellowish brown or yellow. The body and foot are 

 greyish white. 



Dimensions. — The largest specimen measured was 19 mm. long by 

 II mm. wide and 7 mm. high. 



Head. — The head is large and veliform with a longitudinal slit like 

 mouth. It is continued out laterally to form two wide flattened tentacles 

 which like the head itself are completely covered by the mantle. 



Foot. — The foot is long oval and tapering, bluntly rounded in front 

 and passing ofif behind into a pointed tail. 



Rhinophores. — The rhinophores are retractile into a low sheath with 

 a bluntly papillated margin. The stalk of the rhinophore is cylindrical 

 and slightly less than half the total length. The perfoliate clavus is 



