NUDIBRANCHS OF THE VANCOUVER REGION 1 57 



or pigment spots. Examination of the radula and internal organs how- 

 ever showed them to be of the same species. Again three specimens 

 obtained from Newcastle Island on 9th, July 19 19, were of a dingy 

 chocolate shading off to a dark yellow at the border of the mantle, so 

 that the species exhibits a comparatively wide range of colour variation. 

 The colour of this species lasts much longer in spirit or formalin than does 

 that of the preceding species. 



Dimensions.- — Most of the specimens measured were of small size, 

 averaging about 70 mm. long by 32 mm. broad by 15 mm, high. The 

 m.aximum one measured was 172 mm. long by 51 mm. broad by 22 mm. 

 high and this was one of the white specimens although one of the normally 

 coloured ones approached nearly to this size. 



Head. — Larger than in Archidoris montereyensis with a small mouth 

 not in the form of a definite slit but more rounded. The oral tentacles 

 are digitiform about 4.5 mm. long directed antero-laterally. 



Foo/.— The foot is eliptical but tapers somewhat behind and is of 

 yellowish colour. Anteriorly it is bilabiate with a suspicion of a notch. 



RhinopJwres. — The rhinophores can be fully retracted into deep 

 sheaths with tuberculate margins. The stalk is conical and so is the 

 perfoliate clavas which bears about 25 leaves and there is a fairly sharp 

 line of demarkation between them. 



Branchiae. — The six branchial plumes are 3-4 pinnate. They are very 

 large and plumose and when fully expanded cover the posterior portion 

 of the dorsum out to its edges. They are arranged in a circle and joined 

 at their bases by a thin membrane and are of a light colour, frequently 

 white but almost invariably lighter than the body. The large sub-conical 

 anal papilla is situated at the centre of the circle and the renal aperture 

 in front of it and to the right and between it and the bases of the two 

 anterior plumes of the right side. 



Radula. — The radula is pale, deeply grooved short and broad. The 

 teeth are arranged in 25-27 rows. The pleural teeth are large strongly 

 hooked and on the whole similar to those of Archidoris montereyensis. 

 They are about 60 in number in the posterior rows and drop to about 

 55 at the anterior end and the hooks of the teeth in the middle of the row 

 are much more curved than in A. montereyensis: 



The glans penis is unarmed and when everted conical and not slender. 



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

 Bay and designated Montereina being placed in a new genus : the same 

 author later (11) however referred it to the ^ervus, Anisodoris. He has 

 furnished a good description of the internal anatomy and I have been 

 able to obtain confirmation of his account by actual dissection of the 

 cmimals. 



