i68 Transactions of the Royal Canadian Institute 



Family Dorididae Phanerobranchiatae. 



Section Pseudorididae. 



Shape doridiform; Radula varying from moderately broad to very 

 narrow; Teeth differentiated. Ingluvies buccalis present. 



Genus Acanthodoris (Gray). 



Acanthodoris Gray, Fig. Moll. Anim., IV, 1850, p. 103; Guide Moll. Brit. 



Mus., 1857, p. 207. Alder and Hancock, Mon. Brit. Nudibr. Moll., 



VII, 1885, p. 43. Bergh, Gattungen nordisher Doriden, Arch. f. 



Naturgesch. XLV, i, 1879, p. 356; Nudibr. Moll. North Pac. II, 



Proc. Acad. Nat. Sci., Phila., 1880, p. 237; Monogr. d. Polyceraden 



III, Verh. d.k.k. zool-bot Gess. Wien, XXXIII, 1890, p. 988. 



System der Nudibr. Gasterop., 1983, p. 158. MacFarland, Proc. 



Biol. Soc, Washington, Vol. XVIII, 1905, p. 5; Bull. Bur. Fisheries, 



Washington, XXV, 1906, p. 144. 



Body soft subdepressed ; notaeum thickly covered with short villi; 



margin of rhinophore aperture lobed; branchial plumes few, tripinnate, 



arranged in a circle; head wide, veliform; tentacles short lobiform. 



Armature of labial disc of minute hooks below with projecting 

 thickenings of the cuticle. Radula rather narrow; rachis naked; first 

 pleural tooth very large, hooked, external pleural teeth few (4-8). Glans 

 penis armed ; vagina very long. 



Acanthodoris pilosa (O. F. Muller var albescens (Bergh) . 

 Acanthodoris pilosa var albescens Bergh, Proc. Acad. Nat. Sci., Phila- 

 delphia, Pt. I, 1880, p. 97. 

 Body. — The body is oval slightly broader in front than behind. It is 

 plump but not very high. The mantle is thick and wide but the foot 

 appears to be relatively longer than in the other species of the genus for 

 even in preserved specimens it extends beyond the limit of the mantle, 

 from which it is sharply marked off. The whole dorsum is covered with 

 closely set conical papillae some larger than others. They are not re- 

 tractile and even in preserved specimens stick up above the general 

 surface of the body. 



Colour. — The colour agrees most closely with that described for 

 A. pilosa var albescens by Bergh. It is white over dorsum and foot alike 

 and in one specimen showed a faint yellowish tinge. 



Dimensions. — ^The specimens were all small the largest measuring 

 13.5 mm. long by 8 mm. wide and 5.75 mm. high. 



Head. — The head is broad and veliform. It passes out laterally to 



