t 



MUBIDjE— AKVICOLIN^— ARVIOOLA AU8TERDB. 



217 



that "austerus" is not, in nature, niiy more "lypicnl" than curtatm is; in 

 fact, that the (hirk, longer-tailed IllinoiH strain of Pedomys is as iniicli an 

 extreme as curtatus is. The naming of the animal is a mutter of jiidiciuus 

 taste. We prefer to relegate the initial step of the westward departure («". c, 

 "liaydeni") to amterus, and to designate only the extreme of differentiation 

 as var. curtatus. Those of opposite mind, who wish to designate every 

 geographical and climatic modification by a separate binomial, will be 

 obliged, in order to consistence, to do thus: restrict austerus to tiic dark 

 Illinois animal; restrict curtatus to the Calilbrnian, Washington, and Utah 

 animal; adopt haydeni tor some Nebraska skins; invent a new name for 

 others, as our pallid No. 3056 ; ond then leave obout 75 per cent, of Kansas 

 and Nebraska skins unnamed, or else invent a Jifth one for these. In this 

 enumeration we neglect " cinnamomeus'', as founded on a slight individual 

 peculiarity of the enamel folds, which no one — certainly not Professor Baird 

 — would wish to perpetuate by name, now that the real state of the case 

 appears. 



Tablr LV.— X«ararraMiii« oftkMim tpteimeni ({/Fbdomys austkrcs curtatus. 



* stretched to nearly 6 ve Incbea i waa probably about four. 



Among the alcoholics, we find several specimens of curtatus from Utah. 

 They are not in very good condition, showing little respecting the pelage 

 (though the colors appear very light, much as in the Fort Crook specimen), 

 but are unquestionably typical representatives of this extreme variety of aus- 

 terus, and enable us to supply some additional particulars, especially as regards 

 dental characters. They range from 3.25 to 4.00 inches in length ; the tail- 



