436 AMPHISB^NID^. 



An infraocular ; a prseocular ; occipitals 



small 4. subocularis, p. 440. 



Ocular forming a suture with second and 



third labials ; occipitals smaU 5. pretrii, p. 440. 



Ocular forming a suture with second and 



third labials ; occipitals nearly as large 



as frontals 6. leucocephala, p. 441. 



Occipitals twice as large as frontals .... 7. mertensii, p. 441. 



2. The segments of the two median ventral rows more than 

 twice as broad as long. 



a. Pra3frontals distinct ; three 



frontals 20. Jcraussi, p. 447. 



h. Prfefrontals united with the rostral. 



First upper labial distinct ; a supraocular 21. leuciira, p. 447. 

 First upper labial united with the nasal ; 



a small median frontal 22. niuellen, p. 448. 



First and second upper labials united with 



the nasal ; only two anal segments . . 24. liberiensis, p. 449. 



B. jN'ot more than four pra^anal pores. 



1. Two prtefroutals, distinct from the nasals and labials, 



a. Suture between the nasals at least one third as long as 

 that between the pra?frontals. 



a. Temporals small ; 28 to 38 segments in an annulus on 

 the middle of the body. 



* Ocular in contact with the second and third upper 

 labials. 



216 or more annuli on the bodj- ; suture 



between the frontals longer than that 



between the prtefrontals 8. vermicularis, p. 441. 



214 or more annuli on the body ; suture 



between the frontals a little shorter 



than that between the prasfrontals . . 9. darivinii, p. 442. 



** Oculars in contact with the second labial only. 



Four upper labials, two large and two 



small 11. angustifrons, p. 443, 



Two upper labials 13, gracilis, p. 444. 



/3. Temporals small ; 46 segments in an annulus on the 

 middle of the body. 



No occipitals 12. plumhea, p, 443. 



y. A large anterior temporal. 



Head compressed and arched ; 256 annuli 



on the body 14. steindachneri, p. 444. 



180 annuli on the body 18. vioJacea, p. 446. 



