200 REPORT OF NA.TIONAL MUSEUM, 1898. 



a more complete closure of the cranial cavity. The inferior wing of the 

 petrosal is directed inward instead of forward; the parietal fontanelle 

 does not diminish, and the jiremaxillary bone is seen to form a regu- 

 larly decreasing series. The interclavicle and columella diminish in 

 length and disappear, and the splenial becomes smaller and smaller to 

 extinction. The subarticular strengthens the inner rather than the 

 outer wall of the mandible, and the external direction of the coronoid 

 is reversed. 



In approaching the Geckos, the bones of the palate are seen to be 

 thinner and more expanded, and the articular piece of the mandible is 

 lost. In the fnll type the ossification is of the lightest description, and 

 the fascial and basement membranes often present incomplete deposits 

 of bony tissue; thus the parietal and sternal fontanelles disappear. 

 The parietals are not, as usual, united, and there is a diminution (in 

 Vroplates nearly obliteration), of the median or basilar segment of the 

 occipital condyle. There is a temi^oral ala peculiar to this suborder. 



The following is a synopsis of the prevailing characters of the 

 suborders. 



The arrangement adopted in this work is in general that of my sys- 

 tem published in 1864,^ but I have subordinated the divisions some- 

 what differently. This consists chiefly in distributing the divisions of 

 the group I then proposed under the name of Pleurodonta, and regard- 

 ing them as of equal rank with the other three primary suborders — 

 Pachyglossa, Nyctisaura, and Opheosauri. This distribution estab- 

 lishes five additional suborders, and two new ones are added, the 

 Geccovarani and the Anguisauri. The former of these is based on char- 

 acters brought out by Bouleuger in his essay on the classification of 

 the Sauria,^ the latter is made necessary by a different estimation of 

 the characters I described in the memoir above mentioned. The num- 

 ber of suborders is thus eleven, and the families they embrace number 

 twenty-two. For the characters of five of these families I am indebted 

 largely to Boulenger. 



As elsewhere, the orders and families of Sauria can not be arranged 

 in a linear series. There are three lines whose terminal groups are the 

 Chamicleontidje, the Geckonidne, and the Scincidie respectively, and 

 between these most of the families can be arranged. The suborders 

 and families are as follows: 



I. Petrosal not produced anterior to semicircular canal and not articulating above 

 with the parietal; olfactory lobes not nnderarched. Heniiponis 

 mostly calyculate. 



Digits, including metapodials, in opposing groups of two and three about a ceu- 

 trale carpi and tarsi respectively ; tongue papillose, extremity 

 sheathed ; no clavicles Rhiptoglossa. 



Digits all directed forward ; clavicles proximally simple; interclavicle anchor- 

 shaped ; tongue papillose, not sheathed Pachyglossa. 



' Proceedings, Academy Natural Sciences, Philadelphia, 1864, p. 224. 

 2 Ann. Mag. Nat. Hist., XIV, 1884, p. 117. 



