CROrODILlANS, LIZARDS, AND SNAKES. 247 



The scapula has a well-dev^'loped proscapula, and thoie aio two deej) 

 eiiiargiuatious of the coracoid. The steiiiuiu has a narrow lougitudiiial 

 median fontanelle in the G. colkiris, and uo I'outauelle in C. wisUzenii 

 (one specimen of each examined). There are four ribs articulating 

 directly with the sternum on each side, and two by means of each 

 xiphoid rod. The latter are not closely appressed as in some, nor so 

 widely separated as in other Iguanidie. 



Vertebrae without zygosphenal articulation, but the prezygapophyseal 

 faces concave. Cervical vertebr;c eight, the anterior five vertebra?, with 

 six free intercentra in C. wisUzenii and four vertebric wdth live inter- 

 centra in G. collaris; anterior three vertebric without ribs in both 

 species. The neural spines are very low on the dorsal vertebrae, and 

 are a little more elevated on the caudals. The latter have a pro- 

 jecting keel toward the anterior jiart in the G. wisUzenii (wanting 

 in G. eoUaris), which represents the anterior neural spine of IHpso 

 sauru.H dorsaUs. The centra in GrotaphytuH are not segmented. Dia- 

 pophyses are present, but are nowhere long. Short ribs extend to the 

 sacrum. 



The teeth are tricuspid, but in the two species examined the lateral 

 cusps are rudimental. Anterolateral and incisor teeth simple, subequal. 

 The pubes luiite at an exceedingly open angle, and the ])ectiueal proc- 

 ess is submedian. Tuber ischii prominent, a small angle, or crista ilii. 

 Acetabulum entire posteriorly. 



The principal characters in which the skeleton of the Grotaphi/tus 

 differs from Bipsosaurus are the following: Nasal bones shortened in 

 front; no postfrontals ; pineal foramen connected with coronal suture; 

 Meckelian canal i)artlyopeu; two notches of coracoid; xiphoid rods 

 not appressed ; no zygosphen; caudal centra not divided; acetabulum 

 not deeply notched. 



There is a small median posterior lobe of the liver. The left lobe is 

 larger than usual in this family, so as to cause a deep excavation of the 

 posterior border. The colon is not so large as in Bipsofiaurus, and there 

 is no c;ecum. The small intestine is rather long. 



The species of this genus are insectivorous. 1 have taken fragments 

 of grasshoppers from the stomachs of both G. coUarin and G. ivisUzenii. 



Interorbital scales in one or two rows ; other scales above bead larger. Under 

 surface of fore and hind feet with the scales large, carinattMl, and niuerouate. Infra- 

 orbital chain in a series or six or eight sube(|uai scales. 



Scales on the gular fold equal to those below the fore legs. General color greenish 

 or grayish: the back thickly spotted with whitish (in alcoholic specimens; red 

 perhaps in life). A double black collar on each side the neck. Cliin bluish or 

 green, reticulated with yellowish. Young with the large rounded or sub- 

 polygonal' dark blotches in an ashy ground; the back and tail marked with 



transverse bars of whitish C. collaris. 



Scales on the gular fold much smaller than those between the fore legs. General 

 color above grayish, with a hexagonal reticulation of lighter. The interstices 

 here and there abruptly dark brown, a trace only of a black collar on the neck 

 in a single specimen. Chin and throat reticulated. No light spots .C.reticulatus. 



