136 PROCEEDINGS OP THE ACADEMY OP 



of the axis of the body near their superior extremities, and evidently supported 

 a flattened natatory tail, as that of Protonopsis. These neural spines were 

 continued on the posterior third of the dorsal series. The visible, which is 

 probably the greater part of the tail, enters the remainder of the column two 

 and a quarter times, by measurement. 



Sternal and hyoid pieces are not recognizable, though sundry fragments 

 are no doubt to be referred to these regions. An impression resembling that 

 of a raniform scapula, was probably made by that piece. The anterior limbs 

 were short and weak. The humerus is slender; its length equals the distance 

 between the centres of the external nares ; it is apparently not much dilated, 

 nor furnished with a process proximally, but is dilated and grooved distally, 

 and has no condyles. The ulna and radius are separate and slender : the 

 distal extremities of these, with the remaining bones of the anterior limbs, 

 have been lost. 



Of pelvis nothing is recognizable. The femur is slender, much dilated distally, 

 slightly curved in the posterior direction, and without condyles. Its length 

 is equal to the breadth of the cranial table. 



The tibia and fibula are one-half the length of the femur, are slender, most 

 dilated proximally ; the autero-exterfor bone is a little longer', not in contact 

 with the inner distally, which relation I believe to be normal. The tarsus was 

 probably cartilaginous, as in Protonopsis (Menopoma), a faint impression of 

 the outer border remaining. It was broader than long, and without heel-like 

 projections. 



While the great shortness of the lower leg is a Salamandrine peculiarity, 

 the length and slenderness of the digits are quite Lacertian. The leg being 

 extended backward, the exterior or first digit is shortest, and a little less than 

 the second. This is equal to two and one-half phalanges of the fifth, (reckon- 

 ing from its base,) or the. proximal pair of phalanges of the fourth. The 

 fifth is a little shorter than the third, which is scarcely equal to the three 

 proximal phalanges of the fourth. The number of phalanges is 3345 

 4 : among the Salamanders the last two numbers are usually 43. They 

 are without condyles, but exhibit one or two emarginations at their articu- 

 lating surfaces. The length of the basal phalanx of the first digit is two- 

 thirds that of the second ; the latter equals that of the fifth and the second 

 phalanx of the fourth ; these are very little shorter than the basal of the third 

 and fourth. The terminal phalanges are elongate acute, those of the first 

 and fourth slightly curved. They are much less obtuse than in Salamanders, 

 and the animal has probably had weak claws : of these no trace remains. 



A few traces indicate that the dermal integument was covered on the an- 

 terior part of the body, at least, with small and subgranular_ scales. There 

 have been abdominal scales arranged in narrow imbricate series, directed in- 

 ward and posteriorly. Traces of plates are wanting, excepting a small frag- 

 ment lying beside the cervical vertebrae. 



The length of this species from the sacral centre to the interscapular re- 

 gion, was 13 lines ; from the latter point to the end of the muzzle, 12 lines ; 

 to the occipital border, 4-5 lines. Longitudinal diameter of orbit, 3 lines ; 

 frontal breadth, 2 lines ; from border of orbit to border of nostril, 1-5 lines ; 

 breadth of cranial table, 3-75 lines. Length of humerus 3 lines; of femur, 

 3-6 lines; of tibia, 2-3 lines ; of fifth digit, 2-75 lines ; of fourth, 4-2 lines ; of 

 first, 1-8 lines. The portion of the tail preserved measures 5-2 lines. 



If we compare the peculiarities of this genus with those of the Batrachia 

 of the same period, we find it to be distinguished, independently of the ordi- 

 nal characters, from such genera as Osteophorus, Melosaurus, Sclerocephalus, 

 Xestorrhytias, Baphetes, and Brachyops, by the absence of the sculpturing 

 of the cranial bones, the lack of dermal shields, characteristic of most of 

 these, and by the presence of cranial and palpebral scales. The crania of 

 the first genera are much more elongate, and imitate those of some Croco- 



[July, 



