Cope.] 4J4 [ May 21, 



No nasal ; vertebrals equal Hemidipsm* Gthr. 



aaa. Median maxillary teeth shortened. 

 Two nasals and two or more loreals ; anal double ; vertebrals equal. 



Trimorphodon Cope. 



DASYPEIiTINvE. 



No grooved maxillary tooth ; no loreal plate ; scales keeled ; head very 

 distinct Dasyveltis\ Wagl. 



A grooved maxillary tooth ; a loreal plate ; scales smooth ; head little 

 distinct Elachistodon Rhdt. 



Homalopsin^:. % 



I. A grooved posterior maxillary tooth. 



* Muzzle with a pair of tentacular processes. 



One internasal plate ; parietals undivided Herpeton Lac. 



** No tentacular processes. 

 a. Scales keeled. 

 /?. One internasal plate. 



Parietal plates undivided , Homalopsis Kuhl. 



ftp. Two internasal plates. 



Parietal plates subdivided Cerberus Cuv. 



aa. Scales smooth. 

 /9. One internasal plate. 



v. Gastrosteges with two keels. 



Parietal plates subdivided HipiHtes% Gray. 



yy. Gastrosteges not keeled. 

 Nasal plates in contact behind rostral ; eye resting on labial plates 



Sypsirhina\\ Wagl. 

 Nasal plates in contact ; eye bounded below by scales. .Tachyplotus Rhdt. 



Nasal plates separate ; eye on labials Fordonia^ Gray. 



Nasal plates separate ; eye bounded with scales below. . Cantor ia** Gird. 



j3j3. Two internasal plates. 

 Supraorbital and posterior labial plates subdivided ; two anals 



Homalophis Pet. 



Nasals in contact behind rostral ; parietals entire Ferania\ \ Gray. 



Two pairs of prefrontals ; nasal plates separate, undivided ; eye on labials ; 

 anal double Releophis Midler. 



II. Posterior maxillary teeth not grooved. 

 * Scales keeled. 



f Dentition diacranterian. 



* ChamcBtorlus Gthr. 



i lihachiodon Jour. Diodon Owen. A notion Smith. 



JCope, Proceedings Academy Philadelphia, 1861, p. 167. 



§ Bitia Gray. 



|! Kurt, si, is I). * B. Pt. ? Phytolopais Gray. 



If Gerarda Gray. Oampylodon D. <& B. 



** Hydrodipsas Peters. 



-it Trigonurus D. & B. Feranoidcs Carlleyle. 



