scott: toxodonta OF THE SANTA CRUZ beds. 187 
So far as can be determined at present, there are no very marked skull- 
characters which are diagnostic of the present species. In the great 
majority of the skulls found the frontals have large, triangular nasal pro- 
cesses, but these processes vary in size and not infrequently are absent. 
Normally, the upper profile of the skull is nearly straight, or slightly con- 
vex antero-posteriorly, but in several specimens the sagittal crest rises 
quite steeply from the forehead to the occipital crest. In no individual of 
this species have I observed a descent at the forehead, such as is charac- 
teristic, though not invariable, in N. conspurcatus. There is considerable 
variation in the form of the chin and symphysis of the mandible, a varia- 
tion which does not appear to be correlated with age. In some individuals 
the symphysial region is much more depressed, in others more erect and 
abruptly rounded. 
Measurements. 
No. 
No. 
No. 
No. 
No. 
No. 
No. 
15,252- 
15 , 135 - 
15,000. 
15 , 336 . 
I 5 ,i 4 i • 
15,256- 
15,001. 
Skull, length in median base line . 
.420 
?.36 i 
•425 
.448 
•451 
423 
.258 
“ fr. occ. condyles 
•447 
•437 
.472 
.478 
•442 
“ length fr. occ. crest to end of 
nasals 
•354 
•330 
.366 
•389 
.227 
Cranium, length fr. cond. to orbit. 
.242 
.242 
•245 
.228 
?-i55 
Face, length orbit to prmx. . 
.219 
.202 
•215 
.246 
.230 
.123 
Occiput, height 
.161 
•155 
.146 
.076 
width at base .... 
.216 
.217 
“ over condyles 
.098 
.110 
.127 
.096 
Sagittal crest, length .... 
.090 
.066 
.085 
.101 
Zygomatic arch, length fr. glen. cav. . 
.164 
•153 
.168 
.165 
.172 
.167 
.103 
“ “ width. . . 
•075 
.078 
.087 
.106 
•0355 
Cranium, width at constriction 
•055 
•059 
.062 
.060 
•055 
zygomatic width . 
.251 
.258 
.225 
depth at tymp. bulla 
.144 
.121 
.136 
.068 
Face, width over lachrymals 
.112 
• 132 
.127 
•133 
.091 
" “ “ prmx. 
.065 
•075 
.084 
.074 
.048 
“ depth at m 1 .... 
•173 
•153 
.166 
.188 
a a a pi_ 
•145 
.124 
.136 
.129 
.140 
.079 
Nasals, length 
.184 
.180 
.202 
.204 
•095 
Palate, length in med. line . 
.260 
.229 
.269 
•293 
.263 
.150 
“ width at p- 
.032 
.041 
•043 
•043 
.041 
•035 
11 ii 11 ^ 3 . 
.081 
.088 
.098 
.106 
.098 
