234 



U. S. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



through the eye, and pasting round behind it into the sooty of the chin and throat, enclosing an oblong white patch under the 

 eye. Tail as long as the neck and trunk, exclusive of the head ; young? with the body almost entirely black. Length to 

 occiput, 3.80 ; to root of tail, 16.50 ; tail to tip, 11.25 ; fore foot, 1.50 ; hind foot, 2.20 ; height of ear, 1.40. 



A much fuller description of this species, as well as of the Virginia possum, will be found in 

 the report of the Zoology of the Mexican Boundary Survey ; I only introduce here the specific 

 characters of each. 



The present species appears to replace the common possum in Texas and Mexico, as well as 

 in California, and has, doubtless, given rise to the impression of the great range of the former 

 species, though the two are sufficiently distinct on comparison ; the most southern locality I 

 have seen is the city of Mexico. 



The Didelphys californica was first described by Bennett from a specimen caught in North 

 western Mexico, and subsequently received other names ; the D. breviceps, from the same 

 locality, is doubtless identical, as skulls of this genus vary remarkably in the same species, 

 and the great length of the tail, given by Bennett as an important character, has been con 

 siderably reduced by the new measurement of the same specimens by Waterhouse. 



The species is probably abundant in California, though I have not been able to examine any 

 from that region. 



List of specimens. 



