[TAYLOR] 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. MopaLiaA WossNessEeNsKkit, Middendorff, sp. 
Chiton Wossnessenskii, Midd., Bull. Acad. Sci. St. Peters., vol. vi., no. 8, p. 119 
(April, 1847) ; and Mal. Ross., pt. 1, p. 101, no. 6, pl. xi., fig. 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 im 
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. 
PLACIPHORELLA, Carpenter. 
Dall suggests (Proc. U.S. Nat. Mus., 1886, p. 210) that 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, PLACIPHORELLA VELATA, 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. PLACIPHORELLA SINUATA, Carpenter. 
Mopalia sinuata, Cpr., Rept. Brit. Assoc., 1863, p. 648 (August, 1864); and Proc. 
Acad. Nat. Sci. Phila., 1865, p. 59. 
346. PLACIPHORELLA IMPORCATA, Carpenter. 
Mopalia imporcata, Cpr., Rept. Brit. Assoc., 1863, p. 648 (August, 1864); and 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. 
