
MOLLUSCS, VERMES AND HYDROZOA 

Jersey, the Delaware, Schuylkill and the Susquehanna. Common through- 
out New England. 
C. ponderosus, Fig. 147, is the largest Eastern and Middle States 
species but not as common as the foregoing. The 134 inch long polished 
shell is globosely-ovate, very thick and heavy, with a roughened surface 
showing very heavy 
striations of growth; 
of a greenish horn- 
color with irregular- 
ly disposed brown 
and black streaks. 
le has; five: sor six 
whorls, of which the 
body whorl is equal 
to about four-fifths ee meme ee eH 
of the length of the shell, a short spire and a perfect apex, usually eroded. 
The aperture is oval, narrowed above, slightly oblique, and about half the 
length of the shell. The operculum is elongate-ovate with a thin margin. 
The body is a dull brown, the tentacles thick and the eyes prominent and 
black in color. It is ovoviviparous and is found in New York, the Lake 
regions, Ohio, Indiana, [llinois, Michigan, Tennessee and Alabama. No 
experiments with it in the aquarium have been reported. 
Lioptax. These snails are similar to the foregoing but have parallel 
sides, the front truncated and the posterior extremely obtusely rounded. 
The shells are concoidal, elongated and thin, the apex pointed, and the 

operculum with concentric rings. 
L. subcarinata, Fig. 148,is found in Pennsylvania, New Jersey, Ohio, 
Kentucky and some other of the Middle Western States. The elongated 
shell is 34 inch long, of a bright brownish-green color with brown trans- 
, verse lines of growth. 
Of the five whorls, the 
body whorl takes up 
three-fourths of the 
shell; the suture is dis- 
tinct, the apex pointed 
but often eroded, and 
the aperture pear- 
FIG. 148. Lioplax subcarinata. shaped. The lines of 
the operculum are concentric, and the body a dark grey dotted with orange. 
It is ovoviviparous. Fine specimens have been taken from the Delaware 
and Schuylkill rivers and their tributaries. This is the only species of the 

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