CROCODILTANS, LIZARDS, AND SNAKES. 731 



UNGALIIDi!^;. 



In TJngalin tlieie aro no plicae, and in IJ. melanura tliere are only 

 ibur small papilhi' systematically arranged. The sulcus and organ are 

 furcate. 



No species of this family occur in North America. They exist prin- 

 cii)ally in the West Indies. 



AGLYPHODONTA. 



The three families of the Aglyphodonta are as follows: 



Two pulmonary lungs; no trarbcal luug; a coronoid bone Xenopeltid.k. 



One imlmonary lung and a tracheal lung; no coronoid bone; postorbital bone pro- 

 duced forward over the orbit NoTHOPiDyE. 



One pulmonary lung with a rudiment of a second; rarely a tracheal lung; no coro- 

 noid bone ; poatfrontal bone not produced over orbit Colubrid^. 



XENOPELTID^. 



Eyes not covered with a plate ; head with normal shields, with an interparietal added; 

 scales smooth ; anal and subcaudals divided; teeth equal .. A'ewoj>eZ<is Reinwardt. 



Tjje family Xenopeltidie also belongs to the Pahijotropic realm. 



I have been unable to determine the penial structure of the only 

 species of the Xenopeltidie, tjje Xenopeltis unicolor Reinwardt, as all of 

 the four individuals accessible to me are females. 



NOTHOPID^. 



There are two subfamilies of this family: 



No gastrosteges or urosteges Acrochordin.e. 



Gastrosteges and urosteges present Nothopin.«. 



Of the members of these subfamilies I have only examined the hemi- 

 penis of Chersydrus granidatus Cuvier. This bifurcates, but not deeply, 

 and the surface below the bifurcation is smooth. The branches are 

 delicately and not closely spinous. 



ACJROCHortDiisryE;. 



Body compressed, acute below Chersydrus Cuvier. 



Body round, flat lielow 4crochordus Hornstedt. 



The species of this family are of aquatic habit, and live in the rivers 

 of the Malayan Peninsula and tlie islands of Sumatra and Java. But 

 three are known. 



^stoxhopin-^e;. 



Scales above granular, with rows of tul)er(ular scales; urosteges simple; no frontal 



or parietal plates Xenodenniis Reinwardt. 



Scales squamous; urosteges double; head soaly, with frontal and parietal plates. 



Xotliojisis Cope. 

 Scales sciuamous; urosteges single; nine normal liead plates Stoliczkaia Jerdou. 



