668 REPTILES—TRIONYCHIDA. 
mandible compressed laterally, and extended forward; mandibular edges sharp; nos- 
trils situated under rather than at the end of the proboscis; nasal septum smooth or 
without any transversely projecting ridge. 
AMYDA MUTICA LeSueur. 
Leathery Turtle. 
Trionyx muticus, LESUEUR, LECONTE, KIRTLAND, DEKAY, GRay. 
Gymnopus mutica, DUMERIL and BiBRON. 
Amyda mutica, AGASSIZ, COPE, JORDAN. 
Color of upper parts olivaceous to brown, with darker spots upon the carapax; 
beneath more or less whitish without spots or mottled marks; carapax oval, smooth, 
depressed along the vertebral line instead of carinate; anterior margin of carapax naked, 
that is without spines or tubercles; anterior feet with three broad scales which are 
acute above and anteriorly, and with two oblong tubercles behind; tail short; young 
with band on the head and neck, Length, 8 inches. 
Habitat, New York, Pennsylvania, Ohio, Indiana, Michigan, Iowa, and Missouri. 
This species seems to have its range over the waters of the Mississippi, 
and also of the Great Lakes, being according to LeSueur common in 
Lakes Erie and Ontario. In the State it also occurs in the Ohio River. 
The tail in the males is longer than in the females; in the latter it 
does not extend beyond the margin of the carapax. 
GENUS ASPIDONECTES. Wagler. 
Head broader than in Amyda, curving rapidly downward from a line between the 
orbits; mandibles corneous, narrow, and nearly straight; nostrils terminal, with a trans- 
verse projection upon each side of the septum; mouth broader and rounder than in 
Amyda ; feet very broadly palmate, with three claws on each exserted. 
ASPIDONECTES SPINIFER LeSueur. 
Soft-shelled Wurtie. 
Trionyx spiniferus, LESUEUR. 
Trionyx ocellatus, LESUEUR. 
Trionyx ferox, KIRTLAND, DEKAY, not of Schweigger and others. 
Aspidonectes ferox, WAGLER. 
Gymnopus spiniferus, DUMERIL and BIBRON. 
Aspidonectes spinifer, AGASSIZ, COPE, JORDAN, COUES, YARROW. 
Color of carapax dark slate, with oceliate spots above, and often with black dots 
along the margin ; plastron creamy white ; head and neck dark above, light brown, or a 
marbling of black and white beneath ;a lig htstripe extends from the eye backward ; cara- 
pax with a vertebral ridge slightly elevated, its center hard, its margins soft with the ribs 
projecting ; costal plates eight on aside, distinct in adult; anterior margin of carapax with 
a row of spines or denticulated ; fore limbs with transverse elevations ; feet large and 
very broadly palmate; claws on each, three; tail anterior to anus very thick, beyond 
