ON THE BATRACHIA AND REPTILIA OF COSTA RICA. 141 



98. Erythrolamprus venustissimus, Wied. 

 Sipurio. 



99. Xenodon anqustirostris, Peters, Monatsber. K. Preuss. Akad., Berlin. 

 Sipurio. 



100. Stenorhina ventralts, Dum. Bibr., Erp. Gen. vii. 867. 

 Several specimens from Old Harbor. 



The genera related to Stenorhina are numerous, and their characters may be 

 tabulated as follows : — 



I. Internasal plates wanting. 



a. Eostral produced backwards to the frontal. 

 Nasals and first labial confluent. Ficimia, Gray. 



aa. Rostral not separating prefontals. 

 Nasals confluent with first labial; anal entire; prefontals in contact medially. 



S^mphoUs, Cope. 

 Nasals and first labial distinct; anal divided. Cojiopsis, Giinth. 



II. Internasals confluent with nasal plates. 



Dentition glyphodont. Stenorhina, D. B. 



Dentition isodont ; rostral shovel-like. Chilomenisciis, Cope. 



III. Internasals and prefontals distinct. 



a. Internasals separated by backward production of the rostral. 

 Nasals confluent with first labial, Gyalopium, Cope. 



aa. Prefontals separated by forward production of the frontal. 

 Nasals one, distinct from labial. Toluca, Kenn. 



aaa. Prefontals in contact medially. 



/?. Dentition isodont. 



y. Subcaudal scutella divided. 

 No loreal ; anal divided ; two nasals ; rostral produced. Geagras, Cope.* 



* Geagras redimitus, Cope, sp. nov. 



Head not distinct ; muzzle depressed, projecting much beyond the mouth, so that the first 

 superior labial is mostly inferior. Superior face of rostral as wide as length of prefontals; that 

 of internasals narrower, both pairs much wider than long. Frontal large, wide, and produced 

 behind ; parietals as long as frontal, narrowed, bifurcate behind, the notch occupied by a large 

 scale. Superciliary plate small. Nasals elongate, very distinct, the posterior angle produced to 

 the preocular, on one side cut oif, forming a loreal. Oculars 1-1, the posterior barely touching 

 by its posterior angle the anterior angle of the single temporal. Labials five above, tlie eye 

 resthig on the middle of the third, which with the fifth is the longest. Inferior labials six, of 

 which three are in contact witli the pregeneials, and the fourth and largest with tlie short post- 

 geneials. The symphyseal is wide, and in full contact with the pregeneials ; postgeneials not 

 3(5 



