434 
PATAGONIAN EXPEDITIONS : PALEONTOLOGY. 
No. 
No. 
No. 
No. 
No. 
No. No. 
No. 
15,706. 15,707 . 15,708. 15,709, 
15,068. 15,624. 15,999. 
9,122. 
M£, transverse diameter 
.0015 
.0018 
MT, anteroposterior diameter 
.0012 
“ transverse diameter 
.001 
Posterior lower premolar, antero- 
posterior diameter . 
.0015 
.0016 
.0014 
.0015 
,0015 
.0015 
.0014 
Posterior lower premolar, trans- 
verse diameter 
.0008 
.001 
.0008 
.0008 
.001 
.001 
.0008 
Length of inferior molar series on 
alveolar border 
.007 
.007 
.008 
My, antero-posterior diameter 
.0024 
.0025 
.0025 
.0025 
“ transverse “ 
.0015 
.001 5 
.001 5 
.0015 
My, antero-posterior “ 
.002 
.002 
.002 
.002 
.0022 
.002 
“ transverse “ 
.0015 
.0015 
.0015 
.0015 
.001 5 
.0015 
My, antero-posterior “ 
.0017 
.0016 
.0018 
.0018 
“ transverse “ 
.0012 
.0012 
.0014 
.0014 
My, antero-posterior “ 
.0012 
.001 
.001 
“ transverse “ 
.0009 
.0008 
.0008 
Depth of mandible below posterior 
premolar .... 
.0028 
.003 
.0025 
.003 
.0025 
Depth of mandible below My 
.0032 
.0036 
.003 
.0027 
“ “ “ “ My 
.0032 
.0035 
CALLOMENUS Ameghino. 
(Plate LX IV, Figs. 5, $a.) 
■ Callomenus Amegh. ; Nuevos Restos Manfif. Fos. Patagonia Austral, p. 20, 
Aug., 1891 ; Revista Argentina, I, entr. 5 a, p. 306, Oct., 1891. 
Although known only from the mandible and inferior dentition, this 
genus is probably valid, having progressed farther than Palceothentes in 
the elimination of the vestigial antemolars, as the result of a progressive 
' shortening of the lower jaw. The posterior premolar is double-rooted, 
but no longer reaches the general level of the molar series, as it does in 
Palceothentes. It is overlapped and partly concealed by the sectorial blade 
of the first molar. In view of the individual variation in the number of 
vestigial teeth shown by some of the phalangers, Callomenus may be re- 
garded as rather doubtfully separable from Acdestis , which retains four 
of these teeth (Ameghino, 1903, p. 1 7 1 , fig. 98) in addition to the double 
rooted premolar. 
Callomenus is represented in the collection by the right half of a mandible 
