264 



Taphrospi'ys suecatus, Leicly. 



Cope, 1. c, p. 1G4. — Platemys sulcaius, Lekly, Proceedings of the Academy of Philadelphia, 

 1850, 303 ; Cretaceous Reptiles of the United States, 1805, 109, Plate XIX, Gg. 4. 



Greensand of No. 5, New Jersey. 

 Taphrospiiys leslianus, Cope. 



Extinct Batrachia and Reptilia of North America, 1870, p. 100. 



Greensand of No. 5, New Jersey. 

 Tapiirosphys strentjus, Cope. 



Extiuct Batrachia and Reptilia of North America, 10G B, 1870. 



Gteensand, No. 5, of New Jersey. 

 Taphrospiiys nodosus, Cope. 



L. c, p. 100 C, Plato I, fig. 10. 



G-reensand below No. 5, New Jersey. 



PYTHOWOMOllPHA. 



The quadrate bones of the species of this order arc represented in Plate 

 XXXVII In completion of the description of this portion of the skeleton, I 

 would point out the coincidence between the forms of the quadrate bone and 

 other characters employed in the preceding pages, as indicative of generic 

 divisions. To the ridges already described, I would add that the "meatal 

 knob" of Mosasaurus is represented by a ridge or crest in Liodon, and by one 

 less marked in Clidastes; and hence the term "knob-ridge" may be added. 

 The lower part of the great anterior ala turns backward, and is generally 

 continued upward on the outer and anterior side of the knob-ridge; this may 

 be called the "posterior alar" ridge. We then have : proximally , the alar pro- 

 cess : the internal angle: and the internal longitudinal ridge; distaUy, begin- 

 ning in front, the posterior alar ridge; the knob or knob-ridge; median 

 posterior ridge ; and the distal longitudinal ridge. 



Mosasaurus differs from all the other genera in the absence of the inter- 

 nal longitudinal ridge. No other genus is known to possess the median pos- 

 terior ridge, nor is the knob of the same form in any other. M. fulciatus is 

 the only species of the order in which all four of the distal ridges arc present. 

 In M. maximus, the knob is wanting; and in M. gigait/eus, the median poste- 

 rior ridge is nol found. 



