60 



GLAUC0in;iBJ3. 



a. Diameter of body more than 100 times in the total length.. 



]. macrorhynchus, 



[p. 61. 



h. Diameter of body less than 100 times in the total length. 



Snout rounded 2. distanti, p. 62. 



Snout with angular horizontal edge 3. roslrata, p. 62. 



2. Snout not hooked. 



a. First labial reaching, or nearly reaching, the eye. 



Anterior labial broader than the lower 



border of the ocular 4. affinis, p. 62. 



Anterior labial narrower than the lower 



border of the ocular ; nasal completely 



divided into two 5. alhifrons, p. 63. 



Anterior labial narrower than the lower 



border of the ocular ; nasal semidivided. 6. goiidotii, p. 64. 



h. Pirst labial not reaching the eye. 



a. Supraocular nearly twice as broad as long, followed by 

 a single transversely enlarged shield. 



Nasal divided ; length of tail 9 times in 



the total length 7. emini, p. 64. 



Nasal semidivided ; length of tail 13 times 



in the total 8. signata, p. 64. 



(3. Supraocular small. 



* Diameter of body 40 to 57 times in the total 

 length ; rostral not twice as broad as the nasal, 

 not extending to the level of the posterior border 

 of the eyes. 



t First labial smaller than the lower part of the 

 nasal ; first median head-shield considerably 

 longer than broad .... 9. dimidiata, p. 64. 



ft First labial smaller than the lower part of the 

 nasal ; first median head-shield not or but slightly 

 longer than broad. 



Length of tail 17 to 20 times in the total 



length 10. dulcis, p. 65. 



Length of tail 25 to 30 times in the total 



length 16. hrevicauda, p. 67. 



Length of tail 8 to 13 times in the total 



length 17. nigricans, p. 67. 



ttt First labial as large as the lower part of the 

 nasal 11. narirostris, p. 65. 



