134 Transactions of the Canadian Institute. [vol. ix 



Berlin, ann. 1910, p. 231) come to the conclusion that the series of forms 

 which have been referred to the Ascidia echinata of Linn6, cannot be 

 divided into two distinct species. These Pacific specimens agree well 

 with the descriptions that have been given of Arctic specimens. 



B. villosa (Stimpson). 



Syn. Cynthia villosa Stimpson, Proc. Ac. Phil., ann. 1864, p. 160. 



Cynthia castaneiformis v. Drasche, Denk. Ak. Wien, Bd. 48, 



P-373- 

 Boltenia echinata Ritter, Univ. Cal. Publ. Zool., vol. IV, p. 14. 

 Numerous specimens from Departure Bay, Ucluelet, Goose Island 

 and Prince Rupert, from between tides to 30 fathoms, attached to rocks, 

 sea- weed &c. 



In a series of specimens taken at one locality such a range of vari- 

 tion is shown, that it seems impossible to consider the species listed 

 above in the synonymy as distinct. 



Genus, Pyura {sens, restr.) 



Syn. Cynthia, Halocynthia, Pyura and. part. 



Surface rough with irregular warts, corrugations &c. Test usually 

 more or less encrusted with sand. Siphons usually rather long. 

 Siphonal spinules acicular (always ?). 



Aperture of dorsal tubercle bent, directed forwards. Dorsal groove 

 with languets. Six folds on each side. In very young specimens the 

 second and sixth folds are much smaller than the others. Stigmata 

 longitudinal. 



One gonad on each side, the left in the intestinal loop. Each is 

 divided into (usually) two rows of hermaphroditic masses, the genital 

 ducts passing back between these rows and ending near the anus. 



Type species, P. chilensis Molina. 



Michaelsen has described what purports to be Molina's species (Mt. 

 Nat. Mus. Hamburg, Bd. XXI, p. 15). It would be included in the group 

 of species with the above characters and hence becomes the type. Other 

 species are P. dura (Heller), P. jacatrensis (Sluiter), P. riiseana (Traus- 

 tedt), P. karasboja (Oka) &c. I have been able to examine only the one 

 species of this group and consequently the diagnosis given above is more 

 or less tentative. Further study will show the correct limits of this 

 group. The most important characters seem to be the irregularity of 

 the surface, the number of folds and the division of the gonads. 



P. haustor (Stimpson). 



Syn. Cynthia haustor Stimpson, Proc. Ac. Phil. ann. 1864, p. 159. 



Numerous specimens from Departure Bay, Ucluelet, Hope Island 

 and Banks Island, from between tides to 30 fathoms, usually in sand. 



