MAZATLAN BIVALVES 105 
tinide. The genera also are by no means satisfactorily ascer- 
tained ; the same shell having been described by Forbes and 
Hanley as Kellia nitida and Lepton convexum; v. Br. Moll. 
vol. iv., app. p. 255. As the animals of the Mazatlan species 
are entirely unknown, a systematic arrangement of them is 
not attempted; and they are simply grouped under genera 
according to the preponderance of characters. 
Grenos KELLIA, Turt. © 
Kellia, Turton Conch. Dyth. Brit. 1822, p. 56. 
_ Erycina, Payr. non Lam. (sp.) 
Chironia (Laperousii) Desh. Rev. Zool. 1839, p. 356. 
Bornia, sp., Philippi, Enum. Moll. Sic. 1836, p. 13. 
Tellimya, sp., Brown, Ill. Conch. Gr. Br. 
153. KELLIA SUBORBICULARIS, Mont. 
Mya suborbicularis, Mont. Test. Brit. pp. 39, 564, pl. 26, f. 6. 
Tellina sukorbicularis,. Turt. Conch. Dict. p. 179. 
Kellia suborbicularis, ZTurt. Dith. Brit. p. 56, pl. 11, f. 5,6.— 
Alder, Cat. North. & Durh. Moll. p. 93.—Forhes & Hanl. 
Br. Moll. vol. ii. p. 87, pl. 18, f. 9, 9a, 95, pl. O, f. 4.—Searles 
Wood, Crag. Moll. (Paleont. Soc.) Part u. p. 118, pl. 12, 
f.8, a, 6. Clark Moll. Test. Mar. Brit. p. 89. 
Petricola suborbicularis, Gray, Ann. Phil. 1825. 
Erycina suborbicularis, Récl. Rev. Zool. 184A. 
Tellimya suborbicularis, Brown, Ill. Conch. Gr. Br. ed. 2, 
p. 106, pl. 42, f. 14, 15. 
+ Tellimya tenuis, Brown, loc. cit. f. 12, 13. 
?+Tellimya lactea, Brown, loc. cit. f. 10, 11.—(Kellia 1.) B. 4. 
Cat. Br. Moll. pt. 7, p. 83, no. 2.—Loven, I. M. 4A, 310. 
Erycina Geoffroyii, Payr. Cors. 30, pl. 1, f. 3—5. 
Amphidesma physoides, Lam. fide Sow..* 
Bornia inflata, Phil. Moll. Sic. vol. i. p. 14, & vol. i. p. 11. 
After often repeated and most careful examinations of many 
hundred specimens, comparing them with each other and with 
the very minute description in the Br. Moll. as well as with 
every Atlantic specimen that has been accessible, I am unable 
to give any specific characters by which the Mazatlan shells 
. e 
* A. physoides, Zam. Erycina ph. Desh. The description of this shell 
(An. s. Vert. ed. Desh. vi. 130, no. 16, ) will fit any similar species. ‘A. t. orbi- 
culato-globosa, hyalina, vesiculari. Hab, au port du roi George. Peron.” 
