400 J. Hall on Cryptonella, Centronella, Meristella, 
of the shell: appreaDne the median line, tbe band rapidly 
widens, and the front margin is drawn forward. in a Jong acu- 
flected downwards, forming a double vertical plate, not quite 
reaching the ventral valve; the upper edge of which, when 
viewed from the side, is 
: eee z flatly roof-shaped, while 
the lower edge describes 
two  convexities, the 
greater anterior, — 
a notch between them. 
The surfaces of a loop 
and median ps are 
covered with minute ob- 
liquely conical pustules 
in some places S seeming 
to become spinulous.” 
~~ wee d of the atta with the te. 
incbell.—Fig. 3. thar view of the ot 
of a blate form 
"7. Ven and 
Julia ie calarpad to coi passin dora 1 and iP a 6 and 
views of Cryptonella Meta, from the Schoharie grit. 
Fig. 4 is given simply to show the dental Jamel. e ius ver 
tral valve; the delicage impressed line in the centr in 
‘one on each side, described by Prof. Winchell, ue no ey 
the figure. These marks, however, are shown 
and sharavteting the ventral rare or casts of this ee ne | 
nown species of the ge - 
In roast Fifteenth Henk, on ae. State Cabinet, I gave the ‘ 
yi te 8 of the a palye and fig. 9 of the a 
tral. valve, Figures 10 and 11 are dorsal and 
* 
