FAMILY CHELONID®. Pea) 
Description. Shell oblong, narrow in front, broader and more erected behind ; the dorsal 
outline descends rather more abruptly behind ; slightly carinated on the dorsal ridge. The 
first vertebral plate triangular, with its truncated axis behind ; the three following hexagonal, 
the last smaller than the two preceding ; the posterior plate sub-pentagonal, the posterior plates 
distinctly imbricated. Lateral plates large, the anterior irregularly subquadrate ; the two 
following higher than broad, pentagonal ; the last smallest, and also pentagonal; the interme- 
diate marginal plate smallest, sub-quadrate ; the remainder oblong, the four posterior largest ; 
all, except the last two, separated from the shell by a groove. Sternum small, narrow, widely 
emarginate behind, composed of eleven plates, all with concentric angular strie, and minute 
radiating strie ; the anterior intermediate or united; gular very small, triangular; brachial 
small; abdominal plates largest, and apparently immovable. Head and neck capable of pro- 
trusion an inch and a half from the shell. Head very large, pyramidal, four-sided, pointed, 
and slightly truncate in front. Eyes moderate. Nostrils large, contiguous, and placed at the 
extremity of the snout. Two short yellow fleshy tentacula under the chin, and two rather 
larger behind. Skin of the throat and neck granulate. All the feet with acute incurved 
claws, distinctly webbed ; the place of the fifth claw on the posterior foot supplied by a broad 
web. ‘The outer and inner margins of the feet furnished with a cuticular membrane, elevated 
into points. Scaly plates on the anterior surface of the fore feet, and on the under side of the 
hind feet. Tail very robust at the root, with several series of pointed processes, often with a 
horny tip. 
Color. The color and markings of this species not easily detected in the recently caught 
animal, as it is usually covered with an agglutination of mud and aquatic plants; when 
cleansed, the shell appears of an olive brown or green, obscure, radiating dark stripes on the 
lateral plates, and similar longitudinal ones on the marginal plates. Sternum reddish brown 
or flesh-color, with a few indistinct dark blotches. Pupils black ; iris golden. Head black 
or deep olive green. A yellow line on each side passes from the nostrils over the eye upon 
the neck ; another somewhat broader, from beneath the nostrils, and meeting in front, passes 
backward under the eye upon the neck ; a third, shorter, proceeds from near the symphysis 
of the chin, extending on each side of the lower jaw. Feet and tail reddish brown. 
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These dimensions are from a small specimen; the ordinary size is three inches: it is the 
smallest of our tortoises yet discovered. This species is one upon which modern systematists 
have expended much labor, the result of which may be seen in the list of synonimes. 
The Musk Tortoise or Mud Turtle, Mud Terrapin or Stink-pot, (with other equally savory 
popular names,) is to be found in most of our ponds and ditches. It occurs from Maine to 
Florida, but its western limits are unknown. We know from Kirtland, that it occurs in the 
northern waters of Ohio. It appears to be an active, vigorous animal, biting with considera- 
ble vigor when irritated. There appears to be two varieties, of which one is smooth on the 
shell, while the other is sub-carinate. 
