48 MOSASAURUS. 



uniting itself with the maxillary bono and the ossified dental pulp, inserts and fixes 

 the tooth with additional force." 



Again, in comparing the mode of implantation of the teeth of Mosasaums with 

 the hving Monitor and Iguana, Cuvier' observes of the former that " the socles 

 (pedestals) or ossified pulps, which support the teeth, are adherent in hollows or 

 true alveoli contrived in the thickness of the border of the jaw." 



Goldfuss,^ referring to the Maestricht and the Missouri Moaasaums, says, " in 

 both, the crowns of the teeth, invested with shining enamel, are sustained upon the 

 dental capsule which is transformed into an osseous socle, coossified with the 

 alveolus, and they are in part hollow internally and in part solid." 



Owen, in his Odontography, page 258, in reference to Mosasaums, observes that 

 " the maxillary teeth combine the pleodont with the acrodont characters." Further 

 on he continues, "its dentition exhibits in an eminent degree the acrodont character ; 

 the teeth being supported on expanded conical bases anchylosed to the summit of 

 the alveolar ridge of the jaws; no existing Saurian exactly parallels this mode of 

 attachment of the teeth, either in regard to the breadth of the alveolar border or 

 in the relative size of the osseous cones to the teeth which they support. A shallow 

 socket is left where the tooth and its supporting base are shed." The same 

 authority, in a more recent work. Palaeontology, page 279, remarks that " the teeth 

 are anchylosed to eminences along the alveolar border of the jaw according to the 

 acrodont type." 



Pictet, in his Traite de Paleontologie, tome 1, page 504, speaks of the teeth of 

 Mosasaurus as being deprived of true roots and anchylosed to the jaw. 



Gibbes, in his Memoir on the Mosasaurus,^ follows the descriptions of Cuvier 

 and Owen. 



Gervais, in the Zoologie et Paleontologie Francaises, tome 1, page 262, in de- 

 scribing some teeth which he refers to Leiodon, observes that as in Mosasaurus they 

 are inserted in alveoli with which their root is identified by means of the surround- 

 ing layer of cement. In a note he adds the remark, " c'est a tort que Ton decrit 

 les dents des Mosasaiires comme reellement acrodont a la maniere de celles de 

 beaucoup de Sauriens actuels." 



From the fossil specimens I have had the opportunity of examining, the history 

 of the dentition of Mosasaurus, so far as I have been able to trace it from the im- 

 perfect materials, appears to be as follows : — 



The mature teeth of Mosasaurus have curved conical croAvns with long, robust 

 fangs inserted into sockets or alveoli, with which they were at first connected in 

 the ordinary manner by connective tissue, but with which they subsequently became 

 firmly coossified.^ They contain in the interior a large fusiform pulp cavity com- 



' Ossemens Possiles, 143. 



° Schiidelbau des Mosasaurus ; Nov. Act. Acad. C. L. C. Nat. Cur., XXI, 178. Bei beiden sitzen 

 die, mit einem braunen, glanzenden Schmelze uberzogenen Zahnkronen auf der zu eiuen verknocherten 

 Sockel umgcwandelteu, in der Alveole angewachsenen Zahnkapsel, und wird ira Innern tlieils hohl. 

 theils ausgefiillt. 



' Smithsonian Contributions, Vol. II. 



* Goldfoss (Nov. Act. Acad., XXI, PI. 9) has given two figures of teeth with their fangs, which 



