240 TRANS. OF THE ACAD. OF SCIENCE. 
ent from those of any known species that we feel justified in 
characterizing them. 
he basal piece which remains preserved in our s) 
is thin, pentagonal, wider than long, convex, and with slightly 
diverging sides. Its upper edge is concave an onger than 
the — ts ok below is the esigprscatly, of a small, somewhat 
The basal 
is ste angulated i in the middle, and about half as long as 
one of the lateral margins. The =o are nearly plane e and 
nent, rete ctrie, which run in ines neat ly pavalel Ith he 
lateral teral and inferior margins. 
> pseudo- al areas each Sis: an elevated nar 
rongilene + ridge, in the middle of a very large, triangular 
cpecusiaae is oo eagle on anole side of the area 
with closely arrange 2 pore 
RC ECTS A Sa RSA cot na Oe Ee af SESeLg ON RR OSM |S Me 8 yeaa SW LN A i Dee PS NE oe nee ee 
