113, GEOPHIS. 315 



II. Two pairs of cMii-shields. 



A. Maxillary bone extending in front much beyond the palatines ; 



scales perfectly smooth. 



A supraocular ; third upper labial enter- 

 ing the eye ; scales in 15 rows ; ven- 

 trals 147-174 2. semidoliatus, p. 316. 



No supraocular; third and fourth upper 

 labials entering the eye; scales in 17 

 rows ; ventrals 135-144 3. rJiodog aster, p. 317. 



B. Maxillary bone extending in front a little beyond the pala- 



tines. 



Scales in 15 rows, perfectly smooth ; ven- 

 trals 176 4. dugesii, p. 317. 



Scales in 15 rows, striated and keeled ; 



ventrals 129-133 5. sallaii, p. 318. 



Scales in 17 rows, striated and keeled on 

 the posterior half of the body ; ventrals 

 131-154 6. chalyhceus, p. 318. 



C. Maxillary bone not extending in front beyond the palatines. 



1. Upper portion of rostral not measuring more than one 



third its distance from the frontal ; scales in 15 rows. 



Scales perfectly smooth on the anterior 



part of the body, striated and very feebly 



keeled further back 7. hoffmanni, p. 319. 



Scales very distinctly striated and keeled, 



the keel rather strong on the posterior [p. 320. 



part of the body and on the tail 8. dolichocephalus, 



2. Upper portion of rostral measuring at least two thirds its 



distance from the frontal ; scales all smooth, or those at 

 the base of the tail very faintly keeled. 



a. Scales in 15 rows. 



A supraocular ; praefrontals as broad as 



long 9. petersii, p. 321. 



A supraocular ; prsefrontals longer than 



broad 10. championi, p. 321. ^^ 



No supraocular 11. yodmani, p. 322. 



6. Scales in 17 rows. 



Pirst lower labial in contact with its fellow 



behind the symphysial 12. dubius, p. 322. 



Symphysial in contact with the anterior 



chin-shields 13. rostralis, p. 323. 



