NUDIBRANCHS OF THE VANCOUVER REGION 1 59 



DiAULULA SANDIEGENSIS (Cooper). 



Doris (Actinocyclus) Sandiegensis Cooper, Proc. Cal. Acad. Nat. Sci. II, 



1862, p. 204; III, 1863, p. 58. 

 Diaulula sandiegensis Bergh, Proc. Acad. Nat. Sci., Phila; 1880, pp. 40-46; 



MacFarland, Proc. Biol. Soc, Washington, XVIII, Feb. 1905, p. 41; 



Bull. Bur. Fisheries, Washington, Vol. XXV, 1905, p. 122, pi. XXIII . 

 Body. — Somewhat flattened, oval with ends equally rounded. Edge 

 of mantle wide, fairly thick, and extends everywhere well beyond the 

 body with a wavy margin. The tip of the foot just shows beyond the 

 mantle when the animal is crawling actively. The whole dorsum is 

 covered with small closely set villi which give it a soft velvety appear- 

 ance. 



Colour. — MacFarland (11, p. 122) says "The general colour of the 

 dorsum may vary from light yellow to deep brownish yellow or even 

 chocolate", and previously describes the dorsum as "pale yellowish in 

 colour with dark brown or black rings of varying size number and posi- 

 tion". In the specimens I have seen alive amounting to over 50, in or 

 near Departure Bay the colour in the middle region of the back was of a 

 chocolate or even a dark chocolate colour shading off to a lighter brown 

 towards the edge of the mantle but in none could it be described as light 

 yellow save in very small specimens up to 5 mm. and even then the 

 chocolate colour was apparent on the back. One specimen was of lighter 

 colour than the rest but even then hardly pale yellow. The larger spots, 

 often of irregular shape were arranged on the back somewhere on each 

 side of the middle line but hardly to be regarded as forming even in- 

 definite lines. A few smaller spots occur on the back near the middle 

 line and a larger number around the margin. MacFarland notes that 

 the number of spots is subject to variation and may consist of as few as 

 two rows of three. In the specimens here however it is always consider- 

 ably more than that and never as few as in the figure given by MacFar- 

 land so that this together with the difference in ground colour renders 

 the darker more spotted variety hard to recognize from the plate. The 

 colour is retained in preservation for a longer time than is the case in 

 most nudibranchs and traces of the spots can sometimes be seen for a 

 number of years. The spots themselves, particularly the larger ones, are 

 not quite as indicated in MacFarland. Each consists of a light pale 

 greyish white narrow ring, surrounding a thin black ring and then the 

 interior is filled with a deep chocolate colour considerably darker thaa 

 the body colour. 



Dimensions. — MacFarland does not give the measurements of this 

 species but from his figure the length is about 70 mm. and the breadth 



