EMERSON: ANATOMY OF TYPHLOMOLGE. 
59 
The tibia and fibula correspond closely in shape and position to 
the ulna and radius, respectively. The tibia is, however, perceptibly 
larger than the fibula and articulates more completely with the femur. 
The tarsus consists of eight pieces arranged like those of the 
carpus in two rows around a central piece. The fibula articulates 
with the fibulare and the intermedium; the tibia with the inter¬ 
medium and the tibiale. The centrale articulates with all the other 
tarsal elements. Tarsale 4 and 5 are here represented by one piece 
articulating with the metatarsals of the fourth and fifth digits. 
Tarsale 1, 2, and 3 are separate, each articulating with the meta¬ 
tarsal of the corresponding digit. 
The phalanges are twelve in number: one in the first digit, two in 
the second, three in the third, three in the fourth, and two in the 
fifth. Together with the metatarsals, they are similar in shape and 
structure to the corresponding parts of the manus. 
The number and arrangement of both tarsal and carpal elements, 
with the exception of the fusion of tarsale 4 and 5, are identical 
with those of the Spelerpes ruber larva 
Muscular System. 
The muscles are in number and arrangement much like those of 
Proteus and Necturus. On the dorsal, lateral, and ventral surfaces 
of the trunk and tail are simple undifferentiated muscle masses, 
metameric in structure, like muscles of those regions in the fish. 
The more specialized muscles are those of the head, moving the 
jaws and the hyoid apparatus, and of the pectoral and pelvic 
regions, allowing for free movement of the limbs. This arrange¬ 
ment is parallel to that found in most aquatic animals to which the 
movement of the limbs in swimming and walking, and of the jaws 
in feeding, is much more important than movement of the body 
proper, except in simple contortions. 
In Typhlomolge, however, the muscles of the limbs are more 
delicate than those of Necturus. According to Norman, when in 
rapid motion the animal uses its tail as well as its legs, the ordinary 
movements of the animal being very slow. This may explain the 
lack of development in the limb muscles. 
Histologically, too, all the muscles of Typhlomolge differ markedly 
