340 PROCEEDINGS OF THE ACADEMY OF 



peculiarities* takes place at very different points in the advance of develope- 

 ment of animals as compared with each other, all very well know.f If such 

 change took place only in case of unusually prolonged life of certain indi- 

 viduals, we would have an instance of what we call the undependability of a 

 character which we elsewhere rely on. This method of accounting among higher 

 groups especially, for this phenomenon (with which students of nature are so 

 familiar), may be worthy of being placed side by side with that which looks 

 upon it as a state of transition from a condition of inferior to one of supe- 

 rior adaptation to peculiar circumstances of life, or with the usual ' ' acci- 

 dental variation" subterfuge. The number of toes is justly relied on as a 

 safe index to generic groups among Batrachia, Gradientia and Lacertilia, yet 

 in Amphiuma its value is very doubtful, and in Chalcides it is not only not 

 characteristic of the genus, but fails to be constant in the same species. 

 The difference between a limb scarcely developed and one obliterated, pos- 

 sesses no greater significance than the same case among the digits ; the genus 

 Trichiurus illustrates this. As regards the absent members in the genus 

 Mancus, they first appear (i. e. in Chamsesaura) in a condition of compara- 

 tively fulldevelopement. The history of the latter process is, however, neces- 

 sary in order to determine finally the validity of the separation of the genus 

 which I have proposed. 



The position of the two genera is near the Ecpleopodidae, as Dr. Gray 

 arranges them. In the Erpetologie Generate, Chamsesaura is one of the 

 heterogeneous group called Cyclosaura Ptychopleura. 



Char, specif. Generally as in Chamsesaura a n g u i n a. The plates of 

 the head are the same ; they are elongate, especially the interparietal, which 

 is bounded on each side by two parietals. The scales are large, very acute 

 and strongly keeled, in only twenty-two longitudinal rows on the body, 

 (four less than in C. a n g u i n a,) of which the two dorsal are largest. 

 Thirty-six transverse series from temple to vent. Eight scales border the 

 vent : one femoral pore. Tibia shorter than femur, not terminating in a 

 claw, both covered with keeled scales. 



Length of head and body 5 inches 10 lines ; of tail 19 inches 9 lines. 



General color pale brown, whitish beneath, shaded with coppery above. 

 Two brown bands extend from the occiput on the outer half of each median 

 row and all of the row next exterior, to the end of the tail. A trace of a 

 lateral band is seen on the second and third rows below the dorsal. 



This lizard was sent to the Academy of Natural Sciences from Natal, in a collec- 

 tion made by the Rev. Mr. Grout. Other species contained in it were Chamaeleo 

 d i 1 e p i s Leach, Monitor n i 1 o t i c u s Gray, Stellio capensis Dum. , and 

 Agama nigricollis Smith. In the last it may be noted that the liver- 

 brown variations enclose three light brown rhombic spaces on the dorsal line. 

 General tint above rather dark brown. Fourth toe a trifle longer than third. 

 A strong dorso-lateral dermal fold on each side. 



Laeerta strigata Eichw. 



Regarded by Dumeril and Bibron as a variety of L. v i r i d i 3, but believed 

 to be distinct by Gray, Berthold and others. The specimen at my disposal 

 differs from L. viridis, from the same region and from Italy, in its rela- 

 tively smaller head and smaller and more numerous plates of the collar. 

 The temporal shields are quite similar. 



Dactylethra la e vis Gthr. 



Rana ?mas carie n s i s D. B. 



General form slender ; head elongate, narrow, muzzle prominent. Distance 



* i. e. Those which illustrate a greater or less advance towards the extreme of diver- 

 gence <<f the family series. 



t Vide Synopsis of Holcosus and Ameiva, etc , p. 6. 



[August, 



