119 



FAMILY I. TRIONYCHID^IO. THE SOFT-SHELLED TURTLES. 



The (uidcs of tilis Family aro dt'scribt'd as having the body liat 

 and nearly » iriiihir; (ho carapacf or shell is not completely ossified 

 or bony, and is covi-red by a thielc leathery skin which is flexible 

 at the margins. It is lioui this leathery covering that they are 

 called the JA^ather Turtles or Soft-shell Turtles. The bead is long 

 and pointed, with a long Ilexible snout, and the neck is long and 

 slender. The feet are broadly webbed, with 5 toes but only '.i 

 claws to each foot. The soft shelled turtles are all acjuatic and 

 carnivorous in (heir diet and are very voracious creatures. While 

 there are about 30 species known to science only two are found in 

 I'ennsylvania. These belong to dillerent genera and are to be dis- 

 tinguished by the following characteristics: 



A. Nostrils under tip of snout, and circular. Edge of upp^er jaw 

 toothed behind. Genus Amyda. 



AA. Nostrils not under lip of snout, but at the end, crescent 

 shape, with a ridge projecting from each side of the partition in the 

 nose. Edge of upper jaw, not toothed. Genus Aspidonectes. 



Then? is but one species of Amyda, and this is commonly called 

 the Leather Turtle. 



Species 1. Amyda mutica (LeSueur). The Leather Turtle. 



The Leather Turtle is variously known as the Leather-back. 

 Leathery Turtle, Spineless Soft-shelled Turtle, Brown Soft-shelled 

 Turtle and Unarmed Soft-shelled Turtle. It receives its common 

 name, "L'cather Turtle,'' from the fact that the covering is not 

 hard, but leathery, and not shell-like. 



The Leather Turtle is known by the depression along the middle 

 line of the back, with no spines or tubercles along the front margin 

 nor on the back. Tliey aie ukui' or less uniformly olive color, 

 white beneath the feet, not mottled or spotted although the young 

 are spotted above. 



Body flat, nearly circular; carapace not completely ossified; cara- 

 pace and plastron covered by a thick, leathery skin, flexible at the 

 margin. Head long and pointed, with a long, flexible, tubular snout, 

 narrower than that of A. spinifer. Legs well developed, feet broadly 

 webbed, not mottled below; toes long, 5-5, but the claws only 3-3. 

 Front margin of carapace and back smooth. Caraj>ace brown or 

 olive, unicolor or with obscure line-like spots on dull blotches. A 

 depression along the mediodorsal line. Head markings obecure, 

 but forking at base of proboscis. This species seldom attains a 

 length of shell greater than ten inches, but may snmei lines reach 

 twelve inches in length. 



