40 Bulletin American Museum of Natural History. [Vol. XIX, 



bones. The surfaces present the same structure as we have 

 found in the case of the parasphenoid, being furnished with 

 numerous pits. In places, all of these bones present evi- 

 dences of attrition. Near the hinder end of the palatine is 

 seen a portion of the ectopterygoid. 



The floor of the mouth is occupied by two great convex 

 plates which are joined by a transverse suture. The anterior 

 (Fig. 25, gl. h.) has the form of the plate 

 figured by Loomis {op. cit., pi. xxi, fig. 4a) 

 as the entoglossal, although it is smaller 

 than the one figured by this writer. The 

 length and breadth are each about 34 mm. 

 It is strongly convex from side to side. The 

 posterior plate (b. br.) is still more convex 

 than the anterior, especially behind. The 

 hinder border has not been exposed, so that 

 we do not know its form and whether or 

 Fig. 25. Anogmius ^ot it was foUowcd by a third plate. Both 

 sp^dmen^arFig^^^s! thcsc platcs are everywhere pitted, and the 

 mouth. b°\r^, blsit postcrior onc, which has fitted into the con- 

 sohyai.'^ ;^/. -^..gios- ^g^yj^y q£ ^Yie parasphenoidal plate, is worn 

 smooth over a considerable part of its sur- 

 face. It is quite certain that these two plates have been 

 developed on the glossohyal and the basi-branchials. Doubt- 

 less the structure of these plates is the same as that of the 

 plates described under A. altus. Fig- 

 ure 26 illustrates a section across the 

 mouth at about the middle of the 

 basi-branchial plate (Fig. 25, h. br.) 

 and some distance in front of the 

 hinder end of the parasphenoidal plate 

 (Fig. 24, par.). The line above 6. 6r. ni^ 1^-2$ x 

 represents the upper surface of the rut. T" ^laT^^LcLiai! 

 basi-branchial plate. The upper line ^fnel /rATpSpt^lid."' '''" 

 shows the vaulted roof of the mouth 



as formed by the parasphenoidal plate {par.) and the right 

 and left palatines {pal.). 



It is quite certain that the specimen described by Dr. 



Fig. 26 



ec.pt:--^ 



Anogtnius aratus 



From same specimen as 



Diagrammatic 



