: ' ® s., 
262 R. P. Stevens on new Carboniferous Fossils. " 
Length 0°7 of an inch, height 0-4 of an inch. 
Geological positions: in the roof of the Danville coal, and 
unproductive shales; Summit, Columbiana Co., Ohio. 
2. L. dens-mamillata, n. s. Cast twice as long as wide. Beak 
nearly equal to the anterior of the shell, obtuse, does not touch 
the hinge-line, surrounded at its base with 7 distinct nodes with 
corresponding pits—impressions of the pedal muscles. Hinge 
ornamented with 25 mammillary teeth, slightly elevated and 
surrounded by a faint ring. Teeth under the beak are feeble, 
all are posterior. Anterior extremity slightly projecting beyond 
the beak and truncated. Posterior slightly produced, thin and 
rounded. Shell inflated at the umbones. 
Length 0°9 of an inch, height 0°5 of an inch. 
Locality: Battle Creek, Mich. 
Geological position: in ochreous shales belonging to the coal 
measures of Michigan, as is supposed, although found farther 
west than these are generally thought to extend. It is associates 
with an Orthoceras, Nautilus and Bellerophon Urii, which is 
evidently carboniferous, and the following fossils. 
8. LD. nue Shell inflated at the umbones, nearly 
twice as long as wide. Beak at the anterior third appressed to 
the et ae Anterior and posterior extremities nearly e ually 
rounded. Posterior slightly produced and attenuated. Hinge 
line curved, with 25 teeth posterior and 5 anterior. Under the 
beak the teeth are feeble and more robust proceeding backyards, 
the last 10 are large, sharp, and set obliquely to the hinge margi. 
Length 1:4 inch, height 0°6 of an inch. 
Battle Creek, Mich. 
4. L. pandorcformis, n. s. Shell (cast) flat but moderately 10- 
flated at the umbones. Beaks near the middle of the shell, wide 
at the umbones. Anterior extremity broadly rounded. Poste 
rior much produced, attenuated and rostrated. In the oI a 
strong ridge is seen, descending from the beak and curving WW" 
the hinge-line, reaches the posterior extremity. Another strong 
in the rostrated extremity, leaving a wide deep fo 
them. Shell exhibits on the surface strong longitu 
growth, arranged in triple series. Cast resembles t 
and hence the specific name. Teeth scarcely visible, 
10 anterior, 20 posterior, long and slender. 
Battle Creek, Michigan. ms: 
Nucuta (Lamarck).—N. Houghtoni, n. s. Shell equiva - 
longer than wide. Beaks obtuse, not incurved. Anterior a 
tremity truncate. Posterior acute. Surface smooth. The pak 
shows pedal muscular impressions at the base of the beak. sini 
r adductor muscular impression strong, elevated, semicHt™ 
he Pandora, 
probably 
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