THE PHYTOSAURIA OF THE TRIAS 149 



The first and second are in the down-cun.'ed tip of the rostnim. 

 The fourth is probably the last of the long rakehke teeth, for it is 

 the last tooth in the anterior expanded portion. The first tooth, 

 the anterior one. is nearly complete, about 35 mm. long and 9 mm. 

 in diameter at the base. This is probably a substitute for an 

 earher tooth, as the section of the corresponding tooth on the oppo- 

 site side, which is broken ofi* close up to the surface of the rostrum, 

 indicates a tooth as large as those that follow. The second tooth 

 is considerably larger and still presen-'es the sharp point. It is 

 78 mm. in length and has a diameter of 12 mm. at the base. The 

 third tooth is broken off at the base but the section indicates a size 

 for it equal to the fourth. This tooth is 60 mm. long and 9 mm. in 

 diameter. The section of all of these anterior teeth is round with 

 no indications of trenchant edges or fluting. The space between 

 these teeth of the expanded anterior portion is somewhat greater 

 than those bet^-een the remaining teeth. Between the two anterior 

 teeth is a space of fully 18 mm. Bet^'een the first and second, the 

 second and third, and the third and fourth the spaces are approxi- 

 mately 12 mm.. 9 mm., and 10 mm., respectively. The number of 

 teeth in the rostrum back of these cannot be told accurately. It is 

 probably shghtly greater than in .4. grandis. however, as there are 

 about 38 in the space from the tip to the anterior border of the ant- 

 orbital vacuitv' in the former and 34 in the space of the latter. This 

 is inclusive of those of the expanded anterior portion. In A. 

 gracilis the alveoli back of the expanded portion are subequal, 

 averaging about 10 mm. in diameter, and all are roim.d. There is 

 a sHght increase in diameter from the anterior end of the series 

 backward. The spacing is rather irregular. var\-ing between 4 mm. 

 and 9 mm. While the crowns of none of these posterior teeth are 

 preser\-ed in place, they can be described with some degree of cer- 

 tainty". From the locahty where the skulls herein described were 

 collected nearly aU the vertebrate remains were ph^-tosaurian. 

 ^lany loose teeth were picked up as well as several associated with 

 skuUs. There is no group of animals from this locahty other than 

 the ph}-tosaiirs to which the teeth can be ascribed with certainty. 

 A selected series of these teeth is shown in Figs. 8-16. One speci- 

 men (not here figured), a fragment of a skull in which some of the 



