[taylob] marine MOLLUSCA 97 



342. MoPALiA LiGNosA, Gould, sp. 



Chiton lignosus, Gould, Proc. Bost. Soc. Nat. Hist., vol. ii., p. 142 (July, 1846) ; 

 + C. vespertinus, Gould. 



343. MoPALiA WossNESSENSKii, Middendorff, sp. 



Chiton Wossnessenskii, Midd., Bull. Acad. Sci. St. Peters., vol. vi., no. 8, p. 119 

 (April, 1847) ; and Mai. Ross., pt. 1, p. 101, no. 6, pi. xi., fip;. 1-2 (1847). 



These three forms are all extremely common on rocks between tide, 

 marks all through the province. 



As found at Victoria and other localities that I have visited the 

 three are always quite distinct. In fact judging only from specimens in 

 my own collection, I should be inclined to admit at least one other form 

 to specific rank. 



Dr. Dall on the other hand after the examination of a multitude of 

 specimens places lignosa under ciliata as a subspecies, thus reducing our 

 Mopalias to two . 



Typical M. ciliata were not observed by me at Nanaimo last year,, 

 although lignosa and Wossnessenskii were very numerous ; usually ciliata 

 is the commonest form. 



M. Wossnessenskii is very variable in colour ranging from brown to 

 bright red or still brighter emerald green . 



PLACIPHOEELLA, Carpenter. 



Dall suggests (Proc. U.S. Nat. Mus., 1886, p. 210) th&t Placiphor- 

 ella be retained for the group of P. velata, Cpr., and a new subgenus of 

 Osteochiton be formed for P. sinuata and P. imporcata, but for the present 

 we include our three species under the one generic title. 



344. Plaoiphorella vei-ata, Carpenter. 



Not rare in California but only known as British Columbian from 

 one fine specimen found last summer by Professor Macoun, on the rocks 

 at Sooke Harbour, Vancouver Island. 



345. Plaoiphorella sinuata, Carpenter. 



Mopalia sinuata, Cpr., Rept. Brit. Assoc, 1863, p. 648 (August, 1864); andProc- 

 Acad. Nat. Sci. Phila., 1865, p. 59. 



346. Plaoiphorella imporcata. Carpenter. 



Mopalia imporcata, Cpr,, Rept. Brit. Assoc, 1863, p. 648 (August, 1864); aud Proc- 

 Acad. Nat. Sci. Phila., 1865, p. 59. 



Neither of the above species are common. The former occurs at 

 Victoria in ten to thirty fathoms, and has also been taken by me in 

 some numbers on rocks at low tide in Departure Bay. P. imporcata 



Sec. IV., 1895. 7. 



