NATURAL SCIENCES OF PHILADELPHIA. 3H 



I II, III. 



Entirely or nearly entirely Nearctic : extensively Nearctic : extending into 



Nearctic. distributed in Mexi- Continental district of 

 can district of Neo- Neotropical. 



Phrynosoma, tropical R. 



Crotaphytus, Cnemidophorus, 



Holbrookia, Sceloporus, Heterodon, 



Plistodon, Ophibolus, Masticophis, 



Contia, Eutaenia, Elaps, 



* Diadophis, Tropidonotus, Caudisona, 



Pityophis, Rana, Bufo, 



Aromochelys, Spea, Hyla. 

 Amblystoma. 



Sonoran Species 19. Species 13. Species 22. 



IV. Genera confined to the Sonoran district, which extend into the Mexican : 



Uta, Heloderma, Euphryne, Phinaothyra. 



Sonoran species 5. 



V. Genera confined to the Sonoran district which do not extend into Mexico: 



Callisaurus, Dipsosaurus, Uma, Sonora, 



Gyalopium, Chionactis. 



Species 6. 

 VI. Genera chiefly Mexican, which extend into the Sonoran district, (the 

 first two to the Rio Grande) : 



Coleonyx, Hypsiglena, Trimorphodon. 



Species 3. 

 Of the nineteen species embraced in the first table, there are 

 Found in Pacific district, Middle district, Peculiar, 



Phrynosoma douglassii. Phynosoma douglassii, Phrynosoma, 5 sp., 



Crotaphytus collaris, Crotaph. wislizenii, 

 Holbrookia maculata, Holbr. propinqua. 



" texana, Contia isozona. 



Plistodon guttulatus, Diadophis regalis, 



" obsoletus, Amblystoma nebulosum. 



Pityophis bcllona, 

 Aromochelys carinatus. 



1 sp. 8 sp. 10 sp. 



Of the thirteeen species of the second table there ate of the same character 

 Sceloporus graciosus, Sceloporus consobrinus, Ophibolus pyromelanus, 

 Ophibolus boylii, " clarkii, " splendidus, 



Spea hammondii. Eutsenia vagrans, Eutasnia cyrtopsis, 



Rana halecina. " macrostemma, 



" ornata, 

 Tropidonotus validus. 

 3 sp. 4 sp. 6 sp. 



Of the twenty-two species of the third table of genera, the distribution in 

 the same respects is as follows : 



Masticophis tieniatus, Cnemidophorus 6-lineatus, Cnemid. gracilis, 

 Caudisona lucifer. Heterodon nasicus, " melanostethus, 



Masticophis testaceus, Elaps euryxanthus, 



Caudisona conflueuta, Caudisona scutulata, 



" atrox, " pyrrha, 



Bufo dorsalis. " molossus, 



" tigris, 



" cerastes, 



Bufo microscaphus, 

 Hyla arenicolor, 



" cadaverina, 



2 sp. 6 sp. 11 species. 



1866.] 



