^ o. i2(>i. ILL USTRA TIONS OF A MERICAN SHELLS— DA LL. 509 
CHAMA LACTUCA Dall. 
Plate XXXI, figs. s. 10. 
Chamd larfvnt Dall, Rep. Blake Pelec, Bull. Mus. Comp. Zool., XII, 1886, No. 6, 
p. 2(50. 
Dredo'cd ])y the U. S. Coast Survey Steamer llassler at Barbados in 
so to 100 fathoms. U.S.N.M., 64305. 
The shell is of a whitish color with concentric bands of ruddy brown, 
capuliform and thin; the nepionic shell is claret colored and polished. 
This species has the same capuloid form as the 61 nicoUoni Daut- 
zenberg, from the Atlantic coast of France in about 65 fathoms; but 
the latter, which was described in 1893, has broad concentric frills on 
both valves whereas the present species has fluted sculpture on the 
upper, and concentric laminae only on the lower valve. 
AGRIOPOMA new section. 
MERETRIX (AGRIOPOMA) TEXASIANA Dall. 
Plate XXXII, fig. 1. 
Cytherea te.vasiana Dall, Nautilus, V, 1892, No. 12, p. 134. 
Coast of Texas at Galveston and elsewhere. U.S.N.M., 6056. 
Shell white or creamy with a dull surface, rather rudel}' striated in 
harmony with the incremental lines. 
This resembles 3/. sai/ana Convsid { — convesca Say) in a general way, 
l)ut is more elongated and grows to a far larger size. The}' belong in 
the same section of the genus characterized by the colorless shell and 
the rude external sculpture for which (as it does not seem to have been 
difl'erentiated hitherto and is perfectly distinguished from the original 
Callista by its superficial characteristics) I propose the sectional name 
of Agriopoma. 
MERETRIX (TRANSENNELLA) CONRADINA Dall. 
Plate XXXI, figs. .5, 7. 
Cytherea {Transennella) conradina Dall, Proc. U. S. Nat. Mus., VI, Dec, 1883, 
p. 340. 
In mud between tides at Cedar Ke3"s on the west coast of Florida, 
Hemphill; south to Ke}' West and north along the Atlantic coast to 
Cape Hatteras. U.S.N.M., 91993. 
The shell is white with fine zigzag markings of pale yellow in some 
specimens and occasionally a pink sufl'usion internally. It belongs to 
a little group of Veneridce which appears to be restricted to tropical 
and subtropical east American waters and recalls Psephisoi thePaciric 
coast. They are all of small size but do not appear to be viviparous 
like Pse-phla, and are especially characterized by the singular systeiu 
