52 ROYAL SOCIETY OF CANADA 



CJIYPTOMYA. Conrad. 



114. Ckyptomya C'ALIfornica, Coni-jul, sj). 



SpfKinid Cnliforriica, Conr., .lourn. Acad. Nat. Sci. Phila., vol. vii.. pt. 2, p. 'I'M, 



pi. xvii., tig. 11 (18:^7). 



A very common shell in this province. It is found on mwddy 

 shores between tide marks. 



MYA. Linne. 



115. Mta truncata, Linne. 



Syst. Nat., ed. xii., vol. i., pt. 2, p. 1112, no. 26 (17(57). 



This common European shell is generally distributed throughout 

 the province. It prefers a muddy rather than a sandy shore and is not 

 confined to the beach but is often found in deep water. It is a common 

 fossil in the Boulder Clay. 



Mya prcecisa, Irould described from Puget Sound, is said by Car- 

 penter to be a synonym of this species, but other authors refer it to 

 M. arenaria. Gould's description would answer well for a young speci- 

 men of the latter, the original ligure I have not been able to see. 



116. Mya arenaria, Linne. 



Syst. Nat., ed. xii., vol. i., pt. 2, p. 1112, no. 27 (1767). 



This species is a puzzle to me. If it is the M. prtecisa of Gould, or 

 if as Dr. Newcombe asserts it is a frequent fossil in the Boulder Clay it 

 must of course be considered a native of the province. On the other 

 hand, although I had searched the beaches near Victoria for several 

 years previously, I never found a specimen alive or dead until 1888, in 

 which year I dredged a few specimens of the fry in Departure Bay. 



On mj' return to Victoria in 1890, after an absence of two years, I 

 found M. arenaria in thousands in the very spots that I had searched 

 over and over again in previous years and in which it could hardly 

 have existed without my finding it. 



So that whether M. arenaria is a native or not, 1 am fully persuaded 

 that the thousands of specimens now living in every sandy shore from 

 Victoria to the northern extremit}^ of Vancouver Island are descendants 

 of specimens introduced within the last few years. There seems to be 

 pretty good evidence that M. arenaria was introduced near San 

 Francisco with oysters from Eastern America (for as is well known 

 M. arenaria is a very common Atlantic shell), and has multiplied pro- 

 digiously, and possibly it has spread up the coast until our province 

 was I'eached some four or five years ago. 



