EDENTATA OF THE SANTA CRUZ BEDS. 233 



laries are deeper, producing a stronger constriction of the palate at the 

 diastema. 



MEASUREMENTS. 



Upper dentition, length 046 Skull, length occipital condyles to an- 



" " " "& 030 tenor nares 145 



" " " 1~A 0385 Cranium, length to edge of orbit 1 16 



1, length (i. e., antero-posterior diame- Face, length orbit to anterior nares.. . .033 



ter) 006 Occiput, width at base 057 



" width (i. e., transverse diameter). . . .005 Skull, width over lachrymals 055 



^, length 006 Zygomatic arch, length 083 



" width 008 Occipital condyle to glenoid cavity, 



, length 007 length 023 



" width 009 Occipital condyle to &, length 071 



A, length 006 Palate, length in median line 045 



" width 0085 " width at i 020 



, length 0105 " " " preorbital fossae 023 



" width 007 " " " ^ 013 



Skull, length in median line 122 " " " - 0115 



Rostrum, width over 1 034 



The thoracic vertebrae, especially those from the posterior part of the 

 region, are considerably larger than the corresponding ones of H. elongatus, 

 more so than would be expected from a comparison of the skulls alone ; 

 they have higher, broader, thicker and more erect spines. Only on the 

 last thoracic are the small ventral foramina visible. 



The lumbar vertebrae (Plate XLIII, fig. 5, 5" 5*) form a series of four, 

 which in this specimen are in an unusually complete state of preservation. 

 The centra are broad and depressed, increasingly so toward the sacrum, 

 and, although this animal is fully adult, the ventral openings of the canals 

 which traverse the centra are very conspicuous, especially on the second 

 vertebra, becoming quite small on the last. The neural spines are higher, 

 broader, more thickened at the free end and less inclined backward than 

 in H. elongatus ; the transverse processes are quite short, broad and de- 

 pressed, and are curved forward, they are longest on the second lumbar. 

 The accessory articular processes, which are particularly well shown in 

 this individual, are of the type already described as characteristic of the 

 Megalonychidce. Two pairs of such processes are developed, an anterior 

 pair placed upon a shelf-like projection of the neural arch, ventral and 

 external to the prezygapophyses, and a posterior pair which arise from 

 the hinder angulation of the transverse processes. 



