PERENNIBRANCHIATA. 1 5 



of specimens in Prof. Hyrtl's private museum in Vien- 

 na, gives the following: 



"A. Two condyles on the o. o. supraoccipitale. Lon- 

 gitudinal and transverse occipital crests none. Verte- 

 brae 23 Prsemaxillary teeth seven upon each side, 

 no teeth on the o. operculare. From coronoid process 

 to angle of ramus nearly as long as from coronoid to 

 symphysis. Muzzle narrowed, canthus rostralis weak. 



ZOISII. 



A. A. No condyles on the supraoccipitale. 



I. Twenty-three dorsal vertebrae; an occipital crest. 

 Praemaxillary teeth eight, mandibulars twenty-one, a 



few operculars. Coronoid process scarcely developed. 

 Muzzle, and hence the o. o. frontalia exceedingly slen- 

 der; latter with the parietals convex (from drying?) 



CARRARAE. 



II. Twenty-five to six dorsal vertebras ; a longitudin- 

 al occipital crest. 



a. No teeth on the o. operculare ; praemaxillaries 8-9. 



21-2 Mandibulars; from coronoid process to angle 

 much shorter than from former to symphysis ; no groove 

 below coronoid process. Muzzle longer than following ; 

 o. o. frontalia concave medially, parietalia plane ; can- 

 thus rostralis strong xanthostichus. 



a. a. Teeth on operculare; praemaxillaries 8. Man- 

 dibulars 21; from coronoid to angle much shorter than 

 from former to symphysis; groove below coronoid ex- 

 tending anteriorly ; muzzle shorter ; frontals plane, parie- 

 tals, and occipitals concave; canthus strong. 



SCHREIBERSII. 



a. a. a. Teeth on operculare, praemaxillary teeth ten. 9. 

 Twenty-nine (four) mandibulars; coronoid without 



