PLATE 42, 43, 44. 
P. 44 — FIG. 6. 
CONCHYLIOLITHUS Arcites (rostratus) subsca- 
leniformis longitudinaliter striatus, antice in rostrum 
rectum conicum lagve protensus. S. p. 
A fossil shell. The original an Ai'ca. Hinge straight, 
extended. Valves equal, scaleniform. One end of the 
shell lengthened into a straight, smooth, conical rostrum ; 
the other end short, gibbous, and marked from the beaks 
to the margin with very neat, equal and acute stri® : the 
margin in this part of the shell crenulated. The beaks are 
small, pointed and approximate, placed over the shorter 
extremity. 
This is a very elegant and rare fossil. It is found in our 
limestone, but seldom entire. The specimen figured, from 
Bahwell. 
