192 REPORT OF NATIONAL MUSEUM, 1898. 



pioscapular process in many families aud genera. It is present in 

 Ignania and JSTyctisaura, in the last named often decurved and acumi- 

 nate, and in Lophuraj in Acrodonta. It is present among Leptoglossa 

 in Cnemidophorus, and in some Ameivie, while in other Ameiv;e it is 

 wanting. It is wanting generally in Acrodonta, Diploglossa, Theca- 

 giossa, and Leptoglossa, but it is present in Gelestus striatus. It is 

 wanting in Rhiptoglossa. The coracoid is extended anteriorly to the 

 sternum, and it is generally deeply emarginate on its anterior interior 

 border. These emarginations are closed by the procoracoid, which 

 extends to the middle line, aud is only partially or not at all ossilied. 

 There are two coracoid emarginations in most Iguania, exceptions being 

 the terrestrial genera JJrocentrum, Scelo])orics, and Phrynosoma, and 

 the Anolid.e. There are also two iu Varanidie and Teiidie. The Aga- 

 midaj generally have but one, but TJromastix is an excei)tion. There 

 is but one in Auguidte and Scincidae (two in Tiliqua), and none in Helo- 

 dermidai and Cham?eleonidai. 



The iuterclavicle is a very characteristic element in the Sauria. 

 It is wanting iu Chanutleonidie and in some genera with fore limbs 

 rudimental or absent. It is a simple splint in Helodermidie and some 

 degenerate genera. In other families it has a transverse limb on each 

 side, which maybe anterior, producing the "anchor-shaped" form, or 

 median, producing the "cruciform" type. It is anchor shaped in Acro- 

 donta, Iguania, and Thecaglossa, aud cruciform in Dijdoglossa and 

 Leptoglossa. In Nyctisaura it is cruciform, with the lateral processes 

 wide at the base. The sternum is a broad subrhombic plate which 

 articulates by its anterolateral borders with the precoracoid and cora- 

 coid, and by its posterolateral borders with the ribs. In genera with 

 well-developed limbs its principal differences are seen in the nature of 

 its fontanelles when present. In the Agamid* there are two, aud in 

 most Iguauid;e there is one. Exceptions are the genera Polychrus 

 jSauromalus, and DipsosaurKs, where there is no fontauelle. There is 

 none in the Anolida3. In Teiid* and Lacertidju it is present, but in Scin- 

 cidpe it is mostly absent, exceptions being the North American species 

 of Eumeces. The fontauelle is wanting in Geckonida^, Diploglossa, 

 Helodermatoidea, Thecaglossa, and Leptoglossa, with the exceptions 

 above noted. The single median fontauelle is frequently concealed by 

 the median limb of the iuterclavicle. It is nearly divided in some spe- 

 cies of tSceloporus. 



The pelvic arch. — It is characteristic of the Sauria that the ilium 

 is directed upward and posteriorly, and that the obturator foramina 

 are well developed. The latter are only separated from each other by 

 ligament or cartilage, which may sometimes contain some lime salt. It 

 is produced posterior to the ischia in a triangular process, aud less 

 frequently into a similar one in front of the pubic symphysis. The 

 pubic foramen is always present. The pectineal process is present 



