NATURAL SCIENCES OF PHILADELPHIA. 283 



No femoral pores. 



Form slender, scales in Calotes. 1 Lsmanctus. 



equal series, Broncuocela. J 



Form elongate ; eyebrows 

 elevated, tail compress- 

 ed. Gonyocephalus. Ophryoessa. 



Form stouter, scales less 



regular; Hypsibates. Tiaris, 



Femoral pores. 

 Low crested ; small 



hyoid disk. Brachylopbus. Diporophora. 



High crested ; large * 



byoid disc. Iguana. Physignathus. 



Tail with spinous whorls. Cyclura. * * 



Terrestrial types of flattened form. 



Femoral pores. 

 Tail with whorls of 



spiny scales. Hoplocercus. Uromastix. 



Tail long, simple ; scales 



small. Crotaphytus. Liolepis. 



Tail simple, scales large. Sceloporus. * * 



No femoral pores ; preanal pores. 

 Tail with whorls of 



spines. * * Stellio. 



Tail simple, not elongate, 



ear open. Proctotretus. Agama. 



Neither femoral nor anal pores. 



Much flattened, tail short, scales irregular. 



Ear exposed. Phrynosoma. Moloch. 



Ear concealed. (Doliosaurus, s. g.) | MegfuSus!'^^" 



A similar parallel may be drawn between the American Teid;B, and the old 

 world Lacertidae, and in fact between all the families of the Lacertilia Leptog- 

 lossa." I have added to these for comparison two families of the Typhloph- 

 thalmi. Each family embraces one or more series, and these exhibit a re- 

 markable similarity in the relative developmentof the limbs and digits; among 

 the higher groups the parallelisms lie in the an-angement, — as greater or less 

 separation, of the head shields. The Scincidte are cosmopolite ; the Gym- 

 nophthalmid;e, which have the eyelids of their foetus, are Australian; the Sep- 

 sidffi, either larval or senile in head shields, are mostly ^Ethiopian. 



The first comparison of these groups was made by Wiegmann (Herpetolo- 

 gia Mexicana.) who employed, however, only the Scincidas and Lacertidae, and 

 could not include the many types made known since his day. 



From the class Aves I have selected only the homologous series of the Cla- 

 natorial and Oscine Passeres. Naturalists more fully acquainted with the 

 genera could probably increase ihe examples of heterology largely. Each 

 group furnishes us with carnivorous, insectivorous and frugivorous forms ; 

 each with walkers, climbers, and sedentary genera ; each with butcher-birds, 

 thrushes, warblers (not, in song!), wrens and fly-catchers. Each and all of 

 these types are teleologically necessary to any country complete in the wealth 

 of nature, and to each geological period. 



1868.] 



