354 Mr. A. Bell on the Crag-Fauna. 



render the identification of the fossil with the recent shell 

 an easy matter. A. Lyallii has been considered a variety 

 of N. CohholdicBj altered by time, distance, and physical 

 conditions ; but, as the latter shell is a present inhabitant 

 of the Japanese seas [N. msigms, Gould, Otia ConchoL 

 p. 175), there are reasonable grounds for separating the 

 two into distinct species, the more so as they differ in 

 some important particulars from each other. I quote Dr. 

 Baird's remarks : — 



" This species differs from it {i. e. N. Cohholdioi) in 

 being less transversely ovate, in having the beaks more 

 prominent, the posterior row in the hinge fewer in num- 

 ber, and in the costations being stronger in proportion to 

 the size of the shell, and much fewer in number." 



They also differ in the size of the adult shell, in sculp- 

 ture, structure, and tumidity. 



For the opportunity of examining the recent shells I have 

 to thank 8ir Charles Lyell and Mr. Jeffreys. The fossil 

 N. Lyallii occurs at Butley, and the recent shell in 8-12 

 fathoms at Vancouver's Island. 

 *Scacchia elliptica^ Scacchi (Philippi, En. Moll. Sic. t. xiv. 

 f. 8). B.C. Butley. 'W\q. Kellia elliptica of the Mon. 

 Crag Moll. vol. ii. 1. 12. f. 13, does not appear to me to be 

 the same shell as Scacchi's. 



Astarte gracilis, Y^oo(\. (non Mlinst.). Dr. Weichmann in- 

 forms me that the English and German shells are not 

 identical. A. Galeotti, Nyst, corresponds to the Crag spe- 

 cies (see Mon. Crag Moll.). 



Tapes texturata. Lam. A double specimen, nearly perfect. 

 B.C. Waldi-ingfield. 



Donax poUtuSjVoXi. N. C. Walton-Naze, Sutton. 



Glycimeris angusta, Nyst. Norw. C. (Sir Charles Lyell's 

 colL). 



Pandora inwquivalvisj var. ohtusa. Leach. C. C. Gedgrave. 



Gasteopoda. 



^ Cancellaria varicosa, Broc. Conch, foss. Subap. t. 3. f. 8. 

 C. C. Gedgrave. B.C. Waldrmgfield. 



Bonellii, var. dertonensis, Bellardi, Mon. Cane. Pie- 



monte, t. 3. f. 11, 12. C. C. Gedgrave. 

 — contorta. Bast. (Bellardi, Mon. Cane. t. 3. f. 7, 8). 

 C. C. Gedgrave. 



{Columbella) avara, Say (Goidd, Inv. Mass. fig. 197). 



». 



B. C. Waldringfield. This species belongs to the same 

 section {Merica, Ad.) of the Cancellarid^ as C. mitra^formiSy 

 Broc, and C. Fischeri, H. Ad. 

 — costeUtfera, Sow. ( C. Couthouyi, Jay, = C. crtsjxi, Moll., 



