62 MAZATLAN BIVALVES 



but with, tliese exceptions is tolerably constant in character. 

 Colour white, with thin light straw-coloured or yellowish epi- 

 dermis. 



A typical specimen measures loncf. 1'7S, lat. 1'76, alt. l'04i. 



A produced ,, „ „ 1'7, „ 1'6S, „ -92. 



Sah. — Pacific shores of Mexico, Philippi. — Panama, St. Elena, 

 Mus. Cuming, (Hani.) — Panama, not common, C- B. Ad- 

 ams. — Eastern Seas, A. Adams. — Mazatlan ; very common ; 

 Ij'pool ^ Savre Coll. 

 Tablet 259 contains 5 young specimens, the smallest '81 



across. — 260, 5 do. adult. — 261, 5 do. jun. closer strise. — 262, 5 do. 



adult. — 263, 6 sp. distant strise, — 264, 5 sp. adolescent, produced 



foiTu. — 265, 4 do. adult. 



Genus CYCLINA, Desk. 



Cyclina, Desk. Traitd Mem. (1849) i. pi. 14 bis, f. 20-22.— 



JB. M. Cat. Yen. p. 29. 



As the animal of this genus is said by Gray to be like Dosiiiia. 

 while that of Lucinopsis (Forbes Sf Rani. Br. Moll. 1848, vol. i. 

 p. 433) is very different, being closely allied to the Tellinida^. 

 (Clark, Moll. Test. Mar. Brit. pp. 132 et seq.) both genera will 

 have to be preserved ; and the location of different species 

 must await our knowledge of their animals. 



91. Ctclina subqxjadeata, Hani. 



Artemis subquadrata, Proc. Zool. Soc. 1845, p. 11 -.—Descr. Cat. 



App. pi. 15, f. m—Iire. Conch. Icon. pi. 3, f. 15.— ^^oh-. T/ies. 



Conch, p. 661, pi. 141, f. 27. 

 Luciuopis subqiaadrata, P. P. C. Cat. Prov. 

 Cyclina subquadrata, Desh. B. M. Cat. Yen. p. 31, no. 4. 

 = Artliemi8 saccata, Gould, Proc. Bost. Soc. Nat. Hist. J851, 



p. 91 -.—Mex. ^' Cal. Shells, p. 23, pi. 15, f. 2.— (Artemis s.) 



C. B. Ad. Pan. Shells, p. 275, no. 44© —Cyclina s.) Desh. 



B. M. Cat. Yen. p. 32, no. 9.* 



This shell agrees in form and muscidar impressions with 

 Lucinopsis, but the teeth are those of Cyclina. The young shell 

 is much more orbicular in form. I picked a valve from a col- 

 lection of W. Indian shells which exactly resembles this species 

 in all respects except the anterior muscular impression, which 



* ITavinf; just received the [type specimen of A. saccata, through the great 

 kinduess of Dr. Gould, I can speaK to its exact identity. 



