62 MAZATLAN BIVALVES 



but with these exceptions is tolerably constant in character. 

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

 dermis. 



A typical specimen measures long. 1*73, lot. 1*76, alt. 1'04. 

 A produced 1*7, 1'68, '92. 



Hob. Pacific shores of Mexico, Philippi. Panama, St. Elena, 

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

 orns. Eastern Seas, A. Adams. Mazatlan ; very common ; 

 L'pool fy Havre 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 striae. 264, 5 sp. adolescent, produced 

 form. 265, 4 do. adult. 



GENUS CYCLIC A, Desk. 



Cyclina, Desk. Traite Elein. (1849) i.^ pi. 14 bis, f. 2022. 



B. M. Cat. Yen. p. 29. 



As the animal of this genus is said by Gray to be like Dosinia r 

 while that of Lucinopsis (Forbes fy Hani. Br. Moll. 1848, vol. L 

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

 (ClarJc, 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. CYCLINA SUBQUADBATA, Hani. 



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



App. pi. 15, f. 39 Rve. Conch. Icon. pi. 3, f. 15. Sow. Thes. 



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

 Lucinopis subquadrata, P. P. C. Cat. Prov. 

 Cyclina subquadrata, Desk. B. M. Cat. Ven. p. 31, no. 4. 

 = Arthemis saccata, Gould, Proc. Bost. Soc. Nat. Hist. 1851, 



p. 91 : Mex. $ Cal. Shells, p. 23, pi. 15, f. 2. (Artemis s.) 



C. B. Ad. Pan. Shells, p. 275, no. 449. Cyclina s.) Desk. 

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



This shell agrees in form and muscular 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 resemble? this species 

 in all respects except the anterior muscular impression, whick 



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

 kindness of Dr. Gould, I can speak to its exact identity. 



