MAZATLAN BIVALVES 61 
89. Dosinta ANNA, 2. 8. 
D.t. compressa, elongatiore, marginibus equaliter 
arcuatis : suleis concentricis subdistantibus, haud impres- 
sts, medio subobsoletis ; lunuld oblonga, subimpressa ; lacted, 
epidermide flavescente, medio tenuissimad ; dentibus haud valde 
diwergentibus : sinu pallu haud magno, angulato, apice ad 
marginem ventralem muse. adduct. ascendente. 
This fine , and (for a Dosinia) well marked species is known 
from D. ponderosa by its greatly elongated form; from D. 
Dunkeri by its larger size, flatter growth, smoother ribs (the 
difference being at once perceived by drawing the nail along 
the two shells) which are obsolete in the middle ; and especially 
by the shape of the pallial sinus, which in D. Dunkeri almost 
always points to the middle, in this towards the ventral edge 
of the anterior adductor. Long. 2°44, lat. 2°35, alt. 1°12. 
fab.— Mazatlan ; very rare; L’pool Col. 
Tablet 258 contains a young and a full grown specimen. 
90. Dosinta Dunxert, Phil. 
Cytherea Dunkeri, Phil. Abbild. Conch. Cyth. p. 4. no. 5. 
pl. 2, f. 9. (Oct. 1844.) ; 
Artemis Dunkeri, ve. Conch. Ic. pl. 6, f. 34.—Ad. & Rve. Voy. 
Samarang, p. 78, pl. 21, f. 17.—Sow. Thes. Conch. p. 657, “ 
no. 7, pl. 140, f.5.—C. B. Ad. Pan. Shells. p. 274, no. 448. 
Dosinia Dunkeri, Desh. B. M. Cat. Ven. p. 8, no. 9. 
=Artemis simplex, Hanl. Proc. Zool. Soc. Jan. 1845, p. 11: 
Descr. Cat. Ap. pl. 19, f. 41.—Rve. Conch. Ic. pl. 10, f. 9.— 
Sow. Thes. Conch. p. 657, no. 8, pl. 140, f. 6.—(Dosinia s.) 
Desh. B. M. Cat. Ven. p. 9, no. 11. 
Cytherea Pacifica, (Mus. Berol.) Trosch. in Wiegm. Archiv. 
p. 324, (non Dillw.) 
After very patient but altogether ineffectual attempts to 
separate D. simplex of the monographs from D. Dunkeri, in the 
many hundred specimens which have passed under review, I 
am imformed by Mr. Hanley himself that his species is the 
same as Philippi’s; and as the name of the latter bears date a 
few months earlier, it is necessary to preserve it. The shell is 
known by its very rounded, inflated form, more or less produced 
ventrally ; the more produced form is the D. simplex of the 
monographs. It varies somewhat in the closeness of the striz, 
Sept. 1858. g 
