212 REPOKT OF NATIONAL MUSEUM, 1898. 



lous. Clavicle simple proximally. Interclavicle anchor-shaped. Pre- 

 maxillary undivided. Parietal single, receiving the loosely articulated 

 occipital inferiorly. Frontal not underarching olfactory lobes. Tongue 

 papillose, the apex not retractile. 



As to the visceral anatomy, the following points are characteristic: 



Liver short and contracted proximally or seraipyriform, the posterior 

 border more or less emarginate by one or sometimes two notches ; the 

 right lobe more produced than the left, and terminating in a narrow 

 strip which reaches the reproductive cells, (rail bladder partly exposed 

 on the posterior margin. 



Alimentary canal* with stomach, small intestine, and rectum well 

 distinguished, and also a short colon adjacent to the rectum, which 

 frequently presents a short proximal csecum. Corpora adiposa free 

 anteriorly. Kidneys posterior in position; a urinary bladder. Ven- 

 tral mesentery extending to posterior border of liver and beyond it to 

 a fold of the small intestine. 



This superfamily embraces the most vigorous branch of the order 

 and includes the largest species, excepting the Thecaglossa. Its point 

 of contact with the other superfamilies is through the Diploglossa, and 

 especially the ZonuridjTe. In my iirst system of the Sauria I divided 

 the Pachyglossa, as had been done by others, into two superfamilies, 

 and associated one of them with the Chamseleonidie, and the other 

 with the Lejitogloss and Diplogloss superfamilies. This was because I 

 had discovered numerous osteological characters which appeared to 

 justify this arrangement. It is, however, clear that, as various authors 

 have shown, the ChamseleonidjTe represent a distinct superfamily. I 

 am of the opinion also that the points of agreement which I have dis- 

 covered in the anatomy of the acrodont and pleurodont divisions of 

 the Pachyglossa are more important than the differences, and as these 

 points are of the exact grade which define the superfamilies, I return 

 to the system of Wagler and Pitzinger, pointing out at the same time 

 the various osteological characters in which the pleurodont division 

 agrees with other lizards and differs from the acrodont division. 



These two divisions or families differ as follows : 



Dentition acrodont; that is, the shanks of the teeth inclosed between two alveolar 

 walls, with which they are frequently connate Agamid^. 



Dentition pleurodont ; that is, the shanks of the teeth attached laterally to the inner 

 side of the single and external alveolar wall IGUANID^, 



In the Agamida3 the premaxillary bone is nearly always separated 

 below posteriorly from the vomer by the intervention of the maxillaries. 

 The coronoid bone is produced posteriorly and not anteriorly on the 

 outside of the mandibular ramus. The splenial bone is of reduced 

 size and is most frequently wanting; and the articular is much more 

 developed on the inner than on the outer side of the ramus. The groove 

 of Meckel's cartilage is not roofed over between the splenial and internal 

 mental foramina. In all the above characters the Agamidae agree with 

 the Chamneleonidte. 



