CROCODILIANS, LIZAliDS, AND SNAKES. 559 



but 1 have not bad access to suftu;ient material to euable me to refer 

 all tbe genera to the one or tbe otber. In tbe typical members, as the 

 genera Dracwno, Tnpinambis, Ameiva, Cncmidophoru.s, and Ccntropi/x, 

 the pattern consists of numerous delicate, imbricate, transverse laniiiue, 

 which are closely api)lied to each other. Oj^posite the sulcus all the 

 genera display a welt, which has free borders. These are entire in Dra- 

 c(vn(i, and pectinate in Ameiva and Cncmidophorus. Between these and 

 the borders of the sulcus is a rounded welt on each side. The laminaj 

 are at first sublongitudinal, diverging proximad from sulcus; on tlie first 

 welt they turn sharply distad; between this and the welt they make a 

 second chevron, turning proximad. Proximad of the medium welt these 

 laminte meet, forming a curve or chevron turned proximad. In Cnemi 

 dophnrtiti there is one less chevron. In this genus and Ameiva there is 

 a strong fleshy papilla at the apex of each tract between the welt and 

 sulcus. 



A modification is seen in Centropyx (pelviceps). Here there is a nar- 

 row welt opposite the sulcus. On each side of the sulcus a prominent 

 welt diverges from it proximad and approaches the proximal end of the 

 median welt, so as to inclose a space with it. It is transversely plicate, 

 and the inclosed space on each side the median welt has the delicate 

 transverse lamination characteristic of the Teiida\ What is entirely 

 peculiar is the presence at the apex of each of the laminate spaces of 

 a large patch of acute flexible papilla?. 



The plan is the same in the Anadia bogotensis, but the details are 

 quite ditterent. The organ is bifurcate. A strong welt opposite the 

 sulcus is divided into five longitudinal folds, which are crimped trans- 

 versely. The space between this and the sulcus is marked with folds 

 which diverge distad from the welt and become longitudinal, and are 

 transversely crimped. In the longitudinal direction of the plicie this 

 genus diflers from true Teiida?, and it is likely that I]c2)Ieopus and other 

 allied genera are similar. 



In a third type represented by Heteroclonium bicolor a welt bounds 

 the sulcus on each side. The space between these is marked by a few 

 feeble cross folds, and the borders support a single series of closely 

 placed recurved spines. Genera allied to Cophias are likely to pre- 

 sent this structure. 



According to Boulenger — 



The Teiiil;!' comprise a large uumber of species, all of which are inhabitants of the 

 New World, which show great variety of form and scaling. The Teiidio with Lacer- 

 toid and Varanoid a])pearance pass, througli Crocodilurus and NetisHcnrus, into the 

 Cercosaurs (to which the latter is nearer on account of its separated nasal plates, 

 although placed hitherto with the true Teioids). We have, then, several diverging 

 series, the two principal being: Toward Heterodactylus through Arthrosaura, and. 

 toward Cophias through Proctoporus. On the other hand, Cophias resembles Hetero- 

 dactylus in the position of the nostril, and the latter genus leads us through Pero- 

 dactylus to the skink-like genera, such as Iphisa and (i ymnophthalmus, which all agree 

 with Heterodactiiliis in the rudimentary condition (or absence) of the inner linger. 

 Tlie genera difter as follows: The system adopted is a modification of 

 that of Boulenger, but is as yet in a very tentative stage. 



