Rollin H. Baker

“ Remarks.--Cratogeomys castanops consitus is a small pocket gopher (see tables 1 and 2) ; the largest adult available to us is much smaller than the smallest adult of any adjacent subspecies. Specimens from Coahuila assigned to consitus compare favorably with topotypes although those from the vicinity of Jaco are smaller, paler and have a narrower rostrum and smaller maxillary teeth. An immature male trapped three miles northeast of Sierra Mojada is tentatively assigned to consitus. This subspecies seems to be rare in northwestern Coahuila and small colonies are widely scattered. ”

“ This divides Coahuila into a more humid and less elevated northeastern area which is an inland extension westward of the Coastal Plain and a more arid and higher western and southern area which is a part of the "Mesa del Norte" of the Mexican Plateau. In the extreme southeast the still higher elevated plains and intermontane valleys within the Sierra Madre Oriental afford a third habitat for populations of this species. The subspecies of these pocket gophers found in any one of these three habitats show greater affinity to each other than they do to any subspecies found in the other habitats. ”

“ From Cratogeomys castanops bullatus, found to the north, jucundus differs in: Body larger; tail averaging longer; hind foot larger; color of upper parts more ochraceous and less rufous; underparts darker, more buffy and less whitish; skull larger, especially in length, in width across zygomata, in lengths of palate, rostrum and nasals; mastoid and tympanic bullae less inflated; squamosal breadth greater.
Remarks.--Cratogeomys castanops jucundus is large, exceeding subsimus in dimensions of the body, but differing from subsimus in relatively smaller skull. ”