PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 397 



horizontal. They terminate by qnadrate plates that tend to a]>proach 

 the median plane, these horizontal plates protruding in the articulated 

 skull back of the articular facets and the quadrate bones. Broadly 

 oblongf, and raised above the general level of the bone, the articular 

 facets look upwards and a little backwards and outwards. The coro- 

 noid bones are placed, one on either side, slightly posterior to the middle 

 point of the ramus; they project upwards and back- 

 wards as laterally-compressed processes that show ex- 

 ternally still fairly-developed traces of their original 

 sutures ; upon this aspect, also, we observe the irregular 

 sutural line, indicating the point of ending of the deutary 

 portion of the maxilla. 



Each ramus is perfectly smooth beneath, being gently 

 convex from side to side, broadly so longitudinally. 

 The external curve about the symphysis is parabolic in 

 outline, the inner being sharply acute, and, passing back- j'i^J. 

 wards as the inferior ramal border, maintains a more or less parallel 

 position with the external or alveolar border. Anchylosis is never 

 thoroughlj^ established between the dentary elements at the symphysis, 

 this joint having an articulation very similar to the symphysis pubis 

 of anthropotomy, the interested bones coming apart upon very slight 

 provocation in the dried skeleton, showing each articular face to be 

 roughened for an araphiarthrosial joint. 



In the specimens that I have examined, the teeth in the upper jaw 

 seem to invariably pass completely round the alveolar process, while in 

 the lower jaw a few always seem to be lacking on either side of the 

 symphysis; this is also the case in 

 Gerrhonotus, but not so in a specimen ^ 

 of Eumeces sIHltonianus. These teeth 

 are of the pleurodont type; in other ^ 

 words, they are anchylosed to an outer 

 alveolar i>late, as in many of the Iguani- 

 dw. Above their points of union to the V" 

 alveolar i^rocess they are conical in form, 

 pearly white, and glistening, being ar- 

 ranged in a row of some seventeen to 

 twenty in each ramus, the largest being 

 found in the middle and the smallest at either end. The 

 hyoidean arch seems to be largely cartilaginous in structure, though a 

 good deal of bone tissue does exist in it, particularly about the center. 

 In form it resembles the capital letter X, the upper limbs being directed 

 forwards and outwards, the hinder ones backwards and outwards; the 

 body of the hyoid occupying the intersection as an equilateral triangle, 

 with one of the angles placed anteriorly in the middle line, and from 

 which is produced a delicate "glosso-hyal"; the posterior limbs spring- 

 ing from its outer angles, and the anterior ones, apparently by articu- 



