'903.] 



Hay, North American Cretaceous Fishes. 



45 



Fig. 34. A nog- 

 »iiussp. Enlarged 

 view of part of 

 Fig- 33- X 2. 



above, concave below. The ends have evidently been sutur- 

 ally joined to other bones; so that it has apparently been the 

 middle one of a series of at least three bones forming a tritu- 

 rating plate. In this bone, as in No. 21 12, the pitted surface 

 gives evidences of polishing through use. No 

 evidences of teeth are to be found on the cen- 

 tral portions of this plate, but around the 

 borders, especially in front, many small, sand- 

 like teeth are observed. These are clustered 

 on the ridges of dense bone surrounding the 

 pits, as seen in Fig. 34, which represents an 

 enlarged view of the surface of Fig. 3 2 bounded 

 by the two fractures on the upper left-hand 

 border. The pits are shown in black ; the teeth 

 by the small circles. This bone closely re- 

 sembles the one figured by Stewart (Univ. 

 Geol. Surv. Kansas, VI, 1900, pi. Ixvii) as a 

 pharyngeal of Anogmiiis polymicrodus . 



Fig. 35 represents an upper view of another 

 lower dental plate which evidently belongs to 

 some species of Anoginiits. The upper surface 

 is in general convex, but the central and 

 hinder part is somewhat concave. On each 

 side of the concavity a ridge runs forward to 

 about the middle of the length. Here it 

 divides, one branch running outward to the 

 border of its side. The other unites with the 

 corresponding ridge of the other side, and the single ridge 

 thus formed continues to the anterior end of the triturating 

 surface. In front of the pitted mass of dense bone there is a 

 thin expansion of ordinary bone. On the right-hand side of 

 the figure this does not appear, but this is because it has 

 been crushed downward and to the left beneath the part 

 seen. It seems most probable that this bone is the glos- 

 sohyal. It belongs to the same specimen as the piece of tail 

 represented by Fig. 16. Fig. 36 gives a view from above of 

 a caudal vertebra of the same specimen. No. 11 16. There 

 are seen the pits for the reception of the neural arches. 



Fig- 35- A/iog-- 

 tninss\>. No. 1116. 

 X 3. Lower an- 

 terior dental plate. 



Fig. 36. Anog- 

 fiiius sp. No. 1116. 

 X 5. Caudal verte- 

 bra. 



