62 MAZATLAN BIVALVES 
but with these exceptions is tolerably constant in character, 
eee white, with thin light straw-coloured or yellowish epi- 
ermis. 
A typical specimen measures long. 1°73, lat. 1°76, alt. 1°04. 
A produced ,, . H iy Se as na amines Ha tage a 
Hab.—Pacific shores of Mexico, Philippi.—Panama, St. Elena, 
Mus. Cuming, (Hanl.)—Panama, not common, C. B. Ad- 
ams.—Kastern Seas, A. Adams.—Mazatlan ; very common ; 
‘pool & Havre Coll. 
Tablet 259 contains 5 young specimens, the smallest ‘Si 
> across.—260, 5 do. adult.—261, 5 do. jun. closer strize.—262, 5 do. 
adult.—263, 6 sp. distant striz.—264, 5 sp. adolescent, produced 
form.—265, 4 do. adult. 
/ 
Genus CYCLINA, Desh. 
Cyclina, Desh. Traité Elém. (1849) 1. pl. 14 bis, f. 20—22.— 
B. M. Cat. Ven. p. 29. ‘ 
As the animal of this genus is said by Gray to be like Dosinia, 
while that of Lucinopsis (Forbes & Hanl. Br. Moll. 1848, vol. i. 
p. 433) 1 is very different, being closely allied to the Tellinide, 
(Clark k, Moll. Test. Mar. Brit. pp. 182 et seq.) both genera will 
have to be preserved; and the location of different species 
must await our knowledge of their animals. 
91. Cychina suBquaDRaATA, Haul. 
Artemis subquadrata, Proc. Zool. Soc. 1845, p. 11 :—Descr. Cat. 
App. pl. 15, f. 39—Rve. Conch. Icon. pl. 3, f. 15.—Sow. Thes. 
Conch. p. 661, pl. 141, f. 27. 
Lucimopis subquadrata, P. P. C. Cat. Prov. 
Cyclina subquadrata, Desh. B. M. Cat. Ven. p. 31, no. 4. 
=Arthemis saccata, Gould, Proc. Bost. Soc. Nat. Hist. 1851, 
p. 91:—Meex. & Cal. Shells, p. 23, pl. 15, f. 2—(Artemis s.) 
C. B. Ad. Pan. Shells, p. 275, no. 449.—Cyclina s.) Desh. 
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 resembles this species 
in all respects except the anterior muscular impression, which 
* Having just received the {type specimen of A. saccata, through the great 
kindness of Dr. Gould, I can speak to its exact identity. 
