CROCODILIANS, LIZARDS, AND SNAKES. 1127 



DENDKASPIDID.E. 



The single genus of this family is eharacterized as follows: 



Sulcus Viifnrcate; liL'iiiiiuMiis .siiii[»li', calycnlate, liecoiniuj; .siiinoiis at middle; no 

 teeth 1)ebiud IVaij;; attenuate Dt udru^pis Schlegel. 



This family iucludes a half dozen or so of species of the Ethiopian 

 realm. They are of arboreal habits, of green colors, and of elongate 

 form. Their bites are dangerous to men. 



But one family, the Hj^drophid.T, is included in this subdivision. 1 

 have been able to examine but two genera, Hythus and Hydrophis. 

 Specimens of riaturus at my disposal are all females. 



Hemipeuis undivided, spinous to apex, where it is papillose Hydrophis Daudin. 



Hemipeuis bifurcate, spinous to apex Iliidrns Schneider. 



From natural characters the genera are defined as follows. The table 

 is mostly compiled from Giinther, in the Reptiles of British India: 



I. Gastrosteges wide, tlat. 



Two pairs of frontal shields I'httunc^ Latreille. 



II. Gastrosteges wide, with two keels. 



Scales imbricate ; one nasal Aipysiinis Lacepede 



Top of head scaly ; two nasals Pclagoph is Pesters and Doria. 



III. Gastrosteges narrow, rudimentary, or absent. 

 * Nasals separated by frontals. 



Gastrosteges distinct to vent Jiislira Lacepede 



*" Nasals contiguous. 



Head covered with scales behind Acali/ptus DuiiK-ril and Bibrou. 



Head short, entirely shielded; no symphyseal notch Iludrophis Daudin 



Head moderate, entirely shielded; a deep symphyseal notch 



Euhtjdruia Gray 

 Suout long, spatulate Jfj/dnts Shaw. 



The species of this family are aquatic and marine in habitat, and 

 they are found in the seas bounding the Paleotropical and Australian 

 realms. One species — the Hyclnis bicolor — extends its range across the 

 Pacific Ocean and to the coasts of South and Central America, extend- 

 ing as far south as Peru and north t*o Mazatlan, Mexico. It has not 

 been yet found on the coasts of the L^nited States. Admiral McCauley, 

 U. S. ]Sr., informs me that he has sailed through shoals of sea snakes, 

 probably Ilydni.s bivolor, oft" the coast of Peru. The genus Hydrophh 

 is represented b}^ a considerable number of species, while those of the 

 other genera are less numerous. They are mostly dangerous to men 

 who venture into the water which they inhabit. The species of 

 Platurus are more terrestrial in their habits and are sometimes fouml 

 far from the coast. Tlie other species oidy leave the water to depo.sit 

 their eggs. 



