EDENTATA OF THE SANTA CRUZ BEDS. 257 



emarginating the frontals. The preorbital fossae are shallow, except in 

 No. 15,522, in which they are well defined. 



Of the mandible only a fragment of the left ramus, belonging to the 

 type, is preserved ; it seems to be of more uniform dorso-ventral depth 

 and to be less thickened in the dentary region than is usual in this genus. 



In the following measurements it should be observed that the type- 

 specimen (No. 15,564) has been made unduly low and wide by crushing. 



MEASUREMENTS. 



No. 15,564. No. 15,534. N - J 5,522. 



Cranium, length occipital condyle to edge of orbit. .. .108 .096 .101 



Occiput, height 035 .034 .036 



" width at base 055 .049 .050 



Cranium, width at postorbital constriction 036 .030 .030 



" " over lachrymals 060 



Zygomatic arch, length . .075 .064 .070 



Distance, occipital condyle to glenoid cavity 027 .026 



" " " " 071 .065 



Palate, width at 1 020 .022 



" " preorbital fossae 023 .019 .020 



" " & 014 .011 .0125 



" 013 .010 .013 



Mandible, depth below 3- 023 



thickness below 7 013 



Associated with the type are a number of fragmentary vertebrae and of 

 limb-bones in better preservation. The latter are of about the same 

 length as in H. elongatus, but considerably stouter. The humerus is quite 

 robust, with more prominent deltoid ridge than in the last named species, 

 larger epicondylar foramen and much shallower supratrochlear fossa. 

 The femur differs from that of H. elongatus in only a few particulars ; the 

 head is larger, the neck less distinct, the great trochanter smaller and the 

 digital fossa even shallower ; the second trochanter is rather more promi- 

 nent and the third broader proximo-distally ; the shaft is broader and 

 the rotular groove and intercondylar notch are wider. The tibia is some- 

 what heavier and more curved. 



MEASUREMENTS. 



Humerus, length 152 Humerus, width of trochlea 031 



width of proximal end 039 Femur, length from head 168 



" shaft below deltoid " great trochanter .. .161 



area 020 " width of proximal end 063 



