GENERIC KEY 



42. Maxillary teeth normal 



Maxillary teeth with spatulate tip, arranged in 

 groups of three, each group including one 



short, one medium, and one long tooth 



Scaph i odontoph i s 



43.Loreal and preocular both present, two plates 



between nasal and orbit ** 



Loreal or preocular absent, only one plate 

 hetween nasal and orbit Enul ius 



44. Apical pits absent on dorsal scales (Fig. 6) 



102 



Apical pits present (Fig. ])- 



- PI i ocercus 42.Dientes maxilares normales PI iocercus 



Dientes maxilares con apice espatulado, dispues- 

 tas en grupos de tres, cada grupo incluye un 

 diente corto, mediano y largo 



Scaph i odontoph i s 



43. Con loreal y preocular; dos laminas entre nasal 

 y orbita 44 



Sin loreal sin preocular, solo una lamina 

 entre nasal y orbita Enul i us 



44. Sin fosetas *picales en escamas dorsales (Fig. 



6) 102 



-45 Con fosetas apicales (Fig. 7) *5 



Fig. 6. Dorsal scales, without apical 

 pits. Anterior end of scale at top in 

 this figure and Figure 7- 



45. No nuchal collar or band across back of head; 



size generally large 46 



With nuchal collar or band across back of head; 

 size d im i nut i ve Tr imetopon 



46. Poster iormost maxillary teeth enlarged (Fig. 4) 



Le i madoph i s 



je (Fig. 2) 



All maxillary teeth about same size 



-Sordell i na 



47»Dorsals at midbody I7 



Dorsals at midbody fewer than I7- 



-58 

 -48 



48. Vertebral and paravertebral rows subequal 



51 



Vertebral scale row distinctly larger than 

 paravertebrals 49 



45.Mental groove absent (Fig. 

 Mental groove present 



- D i psas 

 50 



Fig. 7' Double apical pits on dorsal 

 scales. May also be single. Usually 

 outer layer of scale must be removed 

 and examined dry under high magnifi- 

 cation to see pits. 



45. Sin banda o collar nucal a traves del dorso de 



la cabeza; generalmente de gran tamano 



46 



Con collar banda nucal a traves del dorso de 

 la cabeza; tamano diminuto Tr i metopon 



46. Dientes maxilares posteriores dilatados (Fig. 4) 



Le i madoph 1 s 



Todos los dientes maxilares aprox imadamente del 

 mismo tamano (Fig. 2) Sordell i na 



47. Dorsales del medio cuerpo I7 58 



Dorsales del medio cuerpo menos de I7 48 



48.Hileras vertebral y paravertebral cas i iguales- 

 51 



Hilera vertebral d i st i ntamente mas grande que 

 paravertebrales 4^ 



45. Sin surco mental (Fig. 8) Dipsas 



Con surco mental 5*^ 



Fig. 8. Dipsas lat i frontal i s . showing ab- 

 sence of mental groove (from Peters, I56O) 



Fig. 5* S i bon nebulata . showing enlarged 

 sixth labial (from Peters, I96O) 



