No. I.] SKELETAL ANATOMY OF AMPHIUMA. 2 1 



The vomers, or vomero-palatines, are present as a pair of 

 thin, narrow sphnts, which extend from the middle of the sub- 

 nasal bands of cartilage backward almost to the antorbital carti- 

 lages. They lie parallel with the trabeculae and a little outside 

 of them. Each is accompanied by a row of dental papillae, five 

 or six in number. These lie a little to the mesial side of the 

 bone. Some of the papillce are already undergoing calcification. 



There are no deposits of bone to represent the maxillae ; but 

 two rows of tooth-papillae, five or six in each, which extend 

 backward from the hinder ends of the alveolar processes of the 

 premaxillas, show where these maxillas will soon appear. 



No bony pterygoids, prefrontals, or nasals are yet to be seen. 



The parasphenoid is a broad but very thin and delicate film 

 of bone underlying the brain from just in front of the foramen 

 magnum forward nearly to the coalescence of the trabeculae, 

 and passing laterally from one trabecula to the other. 



The squamosal is a curved bone that overlies the suspenso- 

 rium and runs upward and backward upon the otic capsule. 

 Its lower border is applied closely to the columella along the 

 anterior half of the latter. 



The lower jaw is furnished with two strongly developed bones. 

 One of these is the dentary. It meets its fellow in front to 

 form a symphysis, and extends backward on the outer side of 

 Meckel's cartilage nearly to the articulation with the suspenso- 

 rium. Arranged along each dentary are about fifteen teeth, 

 only the anterior one of which is anchylosed to the bone. This 

 tooth and the one immediately following it are large and fang- 

 like, and correspond in that respect to the large teeth of the 

 premaxillary. 



The second bone of the mandible, the angular, lying along 

 the inside of the cartilage, extends from the angle of the man- 

 dible half way to the symphysis. 



There is no trace of a splenial bone, and none of an articular. 



As before stated, there is a parostosis connected with the 

 ceratohyal. It lies along the inner and lower side of the carti- 

 lage, running nearly the whole length of the latter. This slender 

 splinter of bone I have repeatedly been able to dissect off ; and 

 having under a cover-glass treated it with hydrochloric acid, 

 have obtained satisfactory effervescence. Wiedersheim {pp. cit., 

 Tafel I., Fig. 8) represents the ceratohyal as having a strip of 



