186 TRANSAC. OF THE ACAD. OF SCIENCE. 
usually more numerous and more densely set with vaulted and 
tubular scales ; anterior wing narrow, lingulate, marked with 
most numerous at the margin; they are crenulated, and seem 
to form the vaulted scales and spines on the costex. 
A large ovate specimen measured in inches :—Length, 2.005 
breadth, site beak to ventral margin, 2.38; length of cardi- 
nal border, 0.85; eaten of left Movie 0.38. Length of a small 
orbicular specim ; breadth, 2.04; length of cardinal 
border, 0.85; depik of le left valve, 0.48. 
6 specimens are very nearly allied to the M Garforthen- 
sis, King, con op pl. xm., figs. 24-25) ; but ours have very 
unequal coste; the right valve is very distinetly 
costate on the i inner side; its anterior ear is long, longiti 
nally rug 5 vom ams s nearly parallel. It is also very ol 
- of the Cotton-wood, and near Cou - - ‘ 
i aemcedatark with Mantilus nected ntalis, Monotis spe 
a, Monois varia, and Pecten Tan ee 
Sore SPELUNCARIA, Schloth He 2 
_ Moworrs ee King, Mon Per. ees 2 pm : 
W specimens one might | 
They differ nearly as mutch fom 
those figured in the Monogrs 
