PLACODONTID^]. 7 



Genus CYAMODUS, Meyer 1 . 



Cranium (fig. 1) not longer than broad, with the premaxillse 

 fused together and not forming a distinct rostrum ; typically two 

 rounded premaxillary teeth on either side ; two or three palatine 

 teeth, of which the crowns are rounded, and the last is much the 

 largest ; two or three maxillary teeth. Mandible with a compara- 

 tively short triangular symphysis, which was not improbably 

 edentulous. 



In the skull No. R. 1644 (p. 9) it is probable that the pro- 

 minence seen on the occiput is the stapes ; while the groove in the 

 zygomatic arch probably indicates the dual origin of this arcade. 



Cyamodus rostratus (Minister 2 ). 

 Syn. Placodus rostratus, Miinster 3 . 



The type species. Of comparatively small size, with three pala- 

 tine and two maxillary teeth • second palatine tooth very small. 

 Eab. Europe (Germany). 



32781. The imperfect crown of a worn palatine tooth, which is 

 apparently the third of either this or the next species ; 

 from the Muschelkalk of Baireuth, Bavaria. So far as 

 can be seen this specimen resembles the third palatine 

 tooth of the type cranium figured by Meyer in the 

 ' Palseontographica,' vol. xi. pi. xxiii. Purchased, 1854. 



Cyamodus muensteri (Agassiz 4 ). 

 Syn. Placodus muensteri, Agassiz °. 



Distinguished from the type species by the presence of three maxillary teeth, 

 which are placed relatively farther back, and by the proportionately larger size 

 of the second palatine tooth. 



Hab. Europe (Germany). 



Unrepresented in the Museum, unless the specimen entered under the preceding 

 specific heading belongs to it. 



1 * Palasontographica,' vol. xi. pt. iv. p. 179 (1863). 



2 Beitrage zur Petrefactenkuncle, vol. i. p. 119 (1839). — Placodus. 



3 Loc. cit. 



4 Recherches sur les Poissons Fossiles, vol. ii. pt.ii. p. 220 (1844).— Placodus. 



5 Loc. cit. 



