NUDIBRANCHS OF THE VANCOUVER REGION 1 75 



Colour. — The body colour is described by Alder and Hancock (i, pt. 

 VI, Fam. I, pi. II) as of a "dull yellowish white marbled with umber 

 brown; the brown markings forming three indistinct bands down the 

 back; those on the sides are generally darkest in colour, but very much 

 interrupted and irregular in form; that on the centre of the back is 

 more uniform but less intense", and further it is noted that the brown 

 markings "are very indistinct and in others entirely wanting; but 

 specimens without markings are comparatively rare". This statement 

 is correct as far as my own observation goes, for in several hundreds of 

 specimens not one has been seen without markings. The description 

 given above applies well to the lighter varieties but in darker individuals 

 the ground colour may be of a chocolate colour. The markings that 

 always appear to be present in varying intensities are a dark ring around 

 the gill bases when contracted, a white patch in the middle line in front 

 of the rhinophores and the two light bands on the dorsum running back 

 from the rhinophores. There is a considerable amount of variation 

 however. 



Head. — The head is broad with a short veil passing ofT laterally into 

 flattened fairly short tentacles directed postero-laterally. The mouth is 

 rounded or even elongated in the transverse direction. 



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

 slightly behind; it is not bilabiate. 



Rhinophores. — ^The subcylindrical rhinophores are completely re- 

 tractile into sheaths which have stnooth non-tuberculate margins. The 

 clavus is about two thirds the total length. It is perfoliate with 14-16 

 lamellae only the upper ones of which meet posteriorly and then they 

 get shorter as they pass down. 



Branchiae.— The branchial plumes vary in number within fairly wide 

 limits, according to Alder and Hancock they may reach 29. I have never 

 seen more than 22 but there is always more than 16. They are small and 

 simply pinnate and arranged in a broad horse-shoe nearly straight an- 

 teriorly with the free ends slightly incurved and retractile within a 

 correspondingly shaped sheath. The anus lies in the much papillated 

 area they enclose. 



This species was named by Linnaeus Doris hilamellata and is a 

 common form on the North-west coasts of Europe. It has been des- 

 cribed by Bergh under the name L. bilamellata var pacifica but apart 

 from the fact that this may indicate it has been found in that region 

 there does not seem to be any reason for creating a separate variety 

 for it. It agrees in all respects with the description given in Alder and 

 Hancock (Pt. VI, Fam. I, pi. II) and as far as my memory serves is the 



