SWALLOW—DESCRIPTION OF FOSSILS. 653 
on the anterior portion; beak long, pointed, incurved ; fora- 
men large, triangular. Dorsal valve not known. 
Length, .75; breadth, .61. 
This shell differs from P. galeatus in being much more 
elongated ; in having a longer and more pointed beak, and in 
having a higher and larger foramen. 
Rare in the Devonian rocks at the base of the Chemung 
Group in Moniteau county. 
RHYNCHONELLA WARRENENSIS, 0. sp. 
Shell large, thick, triangular, plicated, truncated and flat- 
tened in front. Ventral valve flattened, triangular; the an- 
terior and the posterior lateral margins abruptly turned up 
to meet the dorsal valve; the anterior lateral margins curved 
down in the opposite direction ; beak acuminate; sinus wide 
valves is sharply and deeply serrated. Surface marked with 
about fourteen large plications on each valve. 
Length, 1.90; breadth, 1.43; thickness, .99. .. 
this species was discovered in the chert beds of the En- 
“"mital Limestone of Callaway county, by Prof. Kemper. 
Rerzra OsaGEnsis, n. Sp- 
Shell rather large, ovate, gibbous, costate. 
Pe aa highest near the beak, a 
® the anterior margin, somewhat 1 : . 
beak large, elongate, perkeraneds perforation oblique, cron 
Ventral valve 
