46 MALONE JUKASSIC FORMATION OF TEXAS. [bull. 266. 
have been found to be common to both localities), are circunj 
stances which at one time led me to regard the alleged Lima as prob- 
ably identical with the common Pecten of Malone. But that the 
differences of form are considerable, as above shown; that Doctor 
Felix gives two figures of Lima comatulicosta which agree essentially 
with each other in all respects in which cither differs from Pecten 
insutus; that he compares his fossil with a European species of Lima I 
from the coral rag. and that the* peculiar intercostal punctation I 
Imowjn to occur both in Lima and in Pecten, are considerations in 
view of which the assumption that the Mexican fossil has been 
wrongly referred to Lima is not warranted. 
The radially ornamented outer layer of this shell rapidly weathers 
oil', leaving a shiny black surface. so that sometimes the shell appeal! 
smooth or bears only subdued concentric markings. 
The specimen figured represents the more circular phase of the 
jpecies and shows the beaks less pointed than they appear in most 
examples. 
AVKMLII ).K. 
Genus GERVILLIA Defrance. 
( rERVlLLIA CORRUGATA Sp. 11. 
PI. IV. figs, s in. 
Shell inequivalve, v^vy inequilateral, obliquely elongated and 
curved; hinge provided with several cartilage-pits, the one anterioi 
to the beak-- being relat ivelv -mall ; the left valve crescent LC as viewed 
from above, sigmoid as viewed from without, its beak curved forward 
inward, and downward, its postero-basal part curved backward, 
upward, and inward: the right valve (including beak) flattened. 
its posterior umbonal slope monoclinally angulated, the steep and 
narrow post-umbonal slope, separating the anterior, anteropoi 
teriorly flat-convex, proximo-distally flat or slightly concave main 
part of the valve from the relatively depressed posterior wing; ante- 
rior wing small or of moderate size, that of the left valve a little 
contorted, posterior wing rather large, its angle drawn out poste- 
riorly to a point, owing to the strong emargination of its posteriol 
border; umbo of left valve radially corrugated, the adjoining part 
of the left posterior wing similarly ornamented on a smaller scale 
remainder of left and the right valve marked with ordinary growth- 
lines. 
Measurements. — Height, 7 ' 25 mm.; length, .'is mm.; breath, 15 
mm. Portions of several large specimens indicate at least twice these 
dimensions. 
" L. comatula Buvignier. 
6 Height and length taken ;is usual, perpendicular mid parallel to the hinge-line. 
