«5 



Dall evidently found that the various forms of lamellosa 

 were so closely intcrgraded it was not desirable to establish 

 definitive subspecies, and therefore resorted to the expedient 

 of instituting four named varieties in addition to the typical 

 form as figured by Gmclin: franciscana^ from San Francisco 

 Bay; bormica, from Sitka Harbor, Alaska ;w^p/«n<rj, from Cook 

 Inlet, Alaska; and cymica, from Port Ludlow, Washington. 

 These *' varieties" are obviously merely descriptions ol a few 

 local races which might be extended almost indefinitely on 

 the same basis. This has tended to increase rather than lessen 

 the taionomic confusion in this group, as has been indicated 

 by Grant and Gale (1931) and others. Mrs. Ida S. Oldroyd 

 in her survey of the molluscan fauna of our west coast (19^4) 

 cites Dall's varieties but adds the significant note "not known 

 except from the type locality". 



In dealing with the still more heterogeneous forms related 

 to T. lapillus of the Atlantic, Dall differed sharply from Van- 

 atta, since instead of the two species listed by the latter he 

 recognizes four, with several varieties, including lima Martyn 

 typical; T. canaliculata Duclos(i832) typical; 7*. canaliculata 

 var. analoga Forbes (1850); T. canaliculata var. compressa 

 Dall; r. emarginata Deshayes (1839) typical; T.emarginata 

 vsii. osirina Gould (1857); T.emarginata var. projecta Dall; 

 T.freycenetii Deshaye8(i84i). Owing to the amount of "lump- 

 ing" and "splitting" by the several authors the synonomy 

 has become much involved. 



The above arrangement by Dall has a sufficiently wide 

 spread to make possible the labeling of a large number of di- 

 vergent forms, but makes no allowance for the fact that all of 

 these are connected by intermediate types. 



Most recent authors except Mrs. Oldroyd, in dealing with 

 this group have followed the interpretation of V anatta rather 

 than that suggested by Dall . 



A number of fossil forms oiThaisidae derived from Tertiary 

 deposits have been described under various trivial names, but 

 most of these have been placed as synonyms under existing 

 species. 



