1894.] NATURAL SCIENCES OF PHILADELPHIA. 255 



arm white. The cinuamon of ueck forms a point, downwards, in- 

 vading the throat. Ears dusky and very sparsely haired. Whiskers 

 long and coarse, reaching far behind the recumbent ears. Skull very 

 large; its relative dimensions as in S. americanns with two notable ex- 

 ceptions, viz : 1, the alveolar length of molars is less than that of 

 average aiiicricamts, though the skull of niegacephalus is more than a 

 third larger; 2, the coronoid pi-ocess, always developed in amer lean us 

 (and in all other Sitovit/s I have seen), as a reflexed, claw-like 

 process, whose posterior face is iivirr perpendicular, is reduced in 

 me(/<Mrphalns to a thickened knob rounded posteriorly and rising but 

 slightly above the plane of the condylar shaft, and presenting a 

 strong resemblance to the articular terminus of the condyle ; in 

 other words, having not only the appearance but the character of a 

 miniature condyle set upon the base of the true one. 



Meamirrinents. — Total length, 184 mm; tail vertebra?, 81; hind 

 foot, 21-5 ; ear from crown, 14. Skull — Total length, 30-2 ; basilar 

 length, 2o ; zygomatic width, 15-5; length of nasals, 12; incisors 

 to post- palatal notch, 12; length of mandible, 16-3; greatest width 

 of mandible, 7-6. 



I have selected from a series of forty P^'lorida S. a. (/o.<'<ijpi)ii(.'< and 

 a series of nearly two hundred typical S. (nnerica)ui.<, eight of the 

 lai'gest fully adult crania of each form. Average measui-ements of 

 these, in the order just given above for the skull of megaccphalus, 

 are as follows : — 



Sltomijs americanns: 25-9— 1!» -9— 13-4— 10-— 10-5— -13-7 — H-1. 



S. «. rjo.-i.vipinus : 27-3— 20-5— 13-9— 10 -6- 10 -5—14 -1— (r 4. 



It will l)e seen that the Alabama S})ecies has a skull nearly five 

 millimeters longer than average adult americanus. It is further- 

 more about four millimeters longer than the longest skull of a series 

 of three hundred of the aincrminit.-' group which I have examined. 

 Compared with f/ossi/jnuas, whose average, it will be seen, somewhat 

 exceeds typical ainericainis, the differences are still very great. The 

 ty])e is a very old female, which was sent, in company with two young 

 (apparently her own), among a miscellaneous collection of alcoholic 

 animals from Jackson County, northern Alabama. They were the 

 only specimens of Sitoiniis sent by INIr. Sargent, and owing to his 

 sulisecfuent absence from the State, I have been unable to secure any 

 more specimens, to determine if this be the prevailing form in that 

 region. I have since received a large white-footed mouse from Pasco 



