264 The Americau Geologist. May, i900 
Athyris tenuilineata (nov. sp.). 
Plate V, Figs. 31, 32, 33. Djrsal, ventral and profile views of a large 
specimen, natural size. 
Shell ovoid, gibbous, with mesial fold and sinus not ap- 
parent. Brachial valve almost circular. Pedicel valve 
with an incurved, perforate beak. Both valves covered by 
fine, rather crowded lamellose. concentric lines of growth. 
Cardinal extremities rounded. 
This shell may be compared with Athyris hirsuta of high- 
er formations. 
Description made from 12 specimens, collected from the 
soft cherts of the Lower Burlington limestone at Louisiana, 
Mo. 
Atrypa gregeri (nov. sp.). 
Plate V, Figs, q, 10, 11. Dorsal, ventral and profile views of a 
medium sized specimen, natural size. 
Shell ovoid, gibbous, length and breadth nearly equal. 
Brachial valve almost circular, convex. Pedicel valve con- 
vex, with an extended, slightly incurved, perforate beak. 
Neither mesial elevation nor sinus is apparent on any of 
the five specimens examined. 
Surface marked by numerous, fine radiating strict crossed 
by rather strong concentric lines of growth. 
It may be possible that an examination of the inside of 
the valves of this shell will place it in some other genus, 
but externallx' it is apparentl\- very close to Atrypa. 
It is certain Prof. G. C. Swallow collected specimens of 
this shell many j-ears ago. and likely gave it a catalogue 
name but we are not aware that he e\"er published a descrip- 
tion. 
Air. D. K. Greger of Fulton, IMo., collected this fossil 
from the Hamilton beds of Callaway Co., and his collection 
contains a number of specimens The author is indebted 
to Mr. Greger for the fi\e specimens from which the descrip- 
tion has been made out. Specific name in honor of the col- 
lector. 
Camarotoechia elegantula (nov. sp.). 
Plate V, Figs. 44, 45, 46, 47. Dorsal, ventral, [jrofile and front view 
of a small specimen, natural size. 
