+" eatewes Wee are ae 
ength 0-7 of an inch; height 0-4 of an inch. 
Battle Creek, Mich. 
CHONETES (Fischer).—C. Michiganensis, n.s. Shell small, in- 
equivalve. Cardinal area formed at the equal expense of both 
valves, Receiving valve with the disk highly and regular] 
arched. Hinge-line straight, not equal to the width of the shell. 
liquely—the outer stands at right angles to the margin. The 
outer spine is only to be seen in mature specimens—spines more 
in. The punctate strie are more distinct than on ae 
T'wo conspicuous lateral teeth on each aa ) 
the deltidium project inwards and downwards. One arises from 
: Pa larly impressed upon the margin. Entering valve shghtly 
— COheaye, 
shell, 
0-05 of an 
Inch, which space is marked by 80-90 fine, regular striz. . 
ey th 
"100 to be seen only on the interior of the entering valve. 
