488 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 92 
incisor of @. bensoni in Gidley’s paper on these rodents was inter- 
changed with that of ¥. ? minor, so that the tooth shown in his plate 
34, figure 8, is actually that intended to portray C. bensoni rather than 
NV. ? minor. 
Cratogeomys bensoni is a much larger pocket gopher than either 
the later Verterogeomys persimilis or the contemporary JV. ? minor, 
about equaling in size Geomys breviceps and some specimens of Cra- 
togeomys castanops of the Recent fauna of Texas. C. bensoni was 
regarded as belonging to Cratogcomys on the basis of the upper in- 
cisor, which exhibits a single median groove; however, on close inspec- 
tion it appears that there is a very slight inner groove at certain 
points along the length of the incisor. Nevertheless, the development 
of an inner groove is not comparable with that in typical Geomys. 
Some of the other more southern forms such as Platygeomys are char- 
acterized as in Cratogeomys by a single median groove, but the differ- 
ences between these various Geomys-like gophers may not be of more 
than subgeneric importance. 
The lower jaw of C. bensoni is a little slenderer than in the Recent 
forms, Geomys breviceps and Cratogeomys castanops, and the fossa 
for the temporal muscle, though much better developed than in XY. ? 
minor, is not so deep as in G. breviceps or nearly so deep as in Recent 
Cratogeomys. 'The masseteric area and crest are not so expanded 
laterally. The mental foramen is posterior in position and more nearly 
ventral to the anterior extremity of the masseteric crest than in either 
Recent Geomys or Cratogeomys but does not differ in this respect from 
the Recent material so much as do NV. ? minor and N. persimilis. 
The lower cheek teeth have the enamel distributed as in Geomys 
and Cratogeomys, but are a little narrower than in the Recent forms, 
and the reentrants separating the columns of P, are more open than 
in Geomys, although in the type the reentrants do not so effectively 
separate the columns as in Recent Cratogeomys. However, in two 
of the specimens referred to C. bensoni the columns of P, are con- 
nected by a narrow, elongate isthmus almost as in Cratogeomys, 
though possibly not so constricted. Mz, present in the type only of 
C. bensoni, has a slight constricted portion at the posterior margin, or 
grooved as Gidley has indicated. 
BAIOMYS MINIMUS (Gidley) 
The type and only known specimen of this species is a left lower 
jaw, No. 10500, with all the teeth. The jaw and teeth are slightly 
smaller than in Baiomys taylori or the Curtis ranch Baiomys brachy- 
gnathus. The teeth, though a little worn, appear to be more brachy- 
dont than in B. taylori, and as noted by Gidley, the anterior lobe 
of the first tooth is narrow and double cusped. In B. brachygnathus 
