410 THE PUEECO EPOCH. 



transverse extent. The accessory cusp, posterior in A. sectorius and in 

 Haphconus Hneatus, is nearly median on the second and third true molars, 

 though continuous witli the posterior cingulum. Median V shortened; 

 external cusps conic. True molars with an external, as well as anterior 

 and posterior, cingula. No internal cingulum. Enamel smooth. 



Fragments of the mandibles show tliat the masseteric foramen is not 

 impressed anteriorly, but the anterior ascending coronoid ridge is strong. 

 The first inferior premolar had a single robust root. The second is two- 

 rooted. Its crown is robust; and lias a small transverse rudiment of a 

 heel. The second true molar is rather abbreviated. It has two elevated 

 cusps anteriorly, which are confluent at the base, and are supplemented by 

 a small tubercle in the middle of their anterior base, between them. The 

 posterior part of the crown supports three cusps, of which the internal and 

 posterior are small, and the external is an angle from which a ridge extends 

 anteriorly and inwards. The posterior inferior molar is longer, having a 

 heel. The anterior cusps are confluent at the base, and there is a small 

 Ijasal tubercle in front of the inner lobe. There is a narrow cingulum at 

 the internal base of the internal anterior cusp, but at no other part of the 

 crown. 



The infraorbital foramen is above the middle of the second superior pre- 

 molar. There is a mental foramen below the fii'st inferior premolai'. 



Measurements. 



No. 1. 



M. 



LeugtU of bases from superior Pm. iii to M. ii, iuclusivo 023 



Diameters p,n. jji $ anteroposterior 0065 



c traiisverwi 0075 



Diameters p„,. iv^-'"ie'-"P"«t''"or ^>l^ 



( traiiHvorso iXH.t5 



Diameters M.i^•'"t"-"■"l"""«"'"• '^••''' 



I trausverse (MI'JO 



Depth of ramus maudibuli at M. ii 0130 



No. 2. 



Diameters Pm. jj ^ ""teroposterior 0050 



{ transverse OOCO 



Diameters M. iii J ''"'"°l"»'t«"''r 0"^' 



I. iii \ ""'""l 

 ( trausvj 



jrse 0070 



Length of base of inferior Pm. ii 0050 



Depth of ramus at inferior Pm. ii 0100 



Diamctore inferior M. (j U"teropoHtorior 0045 



< transverse 004o 



Length of base iii 



