SOME ACCOUNT, CRITICAL, DESCRIPTIVE, AND HIS- 

 TORICAL, OF ZAPUS HDDSONIUS. 



By Dr. Elliott Coues, U. S. Army. 



Having' occasion to inspect specimens of this qiiadrupedj collected 

 under the direction of Professor Hayden, I have been led into a further 

 investigation of the species, and have examined the whole of the mate- 

 rial contained in the National Museum, Smithsonian lustitutiou, as well 

 as a considerable portion of the literature bearing upou the subject. 

 The present brief article, sketched with j)leasure at Professor Hayden's 

 request, is incidental to three main points determined, namely : — 

 I. There is at present only one known species of Zapus. 



II. The animal, usually referred to the Muridce, differs from the 31u- 

 ridce to a degree warranting the recognition of a family Zapodidce. Such 

 appreciation of the characters afforded was made in 1872 by Dr. Gill, 

 who erected a family {JaciiUdce) for its reception. I may here allude to 

 the presence of an upper premolar, not found in Mnridce proper; the 

 different and peculiar construction of the auteorbital foramen ; and the 

 saltatorial development of the hind limbs. These and other characters 

 are amplified beyond. 



III. None of the various generic names which have been applied to 

 Zapus hudsonius are tenable according to recognized rules of nomencla- 

 ture. Of these, Dipus and Gerbillus are too obviously inapplicable to 

 require comment. Jaculus of Wagler (1830) belongs here ; but the name 

 had been used before in an entirely different connection. Meriones is in 

 similar case; its original application by Illiger was to another type. 

 Though it was subsequently transferred by Frederic Cuvier to the present 

 animal (lUiger's being already provided with a name), it cannot stand in 

 this connection ; for no synonym of one genus shall iDecome the tenable 

 name of another. A new name, therefore, being required, Zapus* is pro- 

 posed; the introduction of the term, of course, necessitating corespond- 

 ing change in the appellation of the family. 



Family ZAPODID^. 



' ■CStCofamih/ Dipodbife, Baird, M. N. A. 1857, 428. 

 = Family JacuUdce, Gill, Arraugement of the Families of Mammals, 1872, 20. 



GexXUS zapus, Coues. (g. n.) 



Dipus, sp. ; GerhiUus, sp., Aliq. 



Meriones, F. Cvyikr. Dents cles Mammif eres, 1825 ?, p. — . — Audubon & Bachman, Q N. A. 



ii, 1851, 251. JSfot of Illiger, 1811. 

 Jaculus, Wagler, Syst. Amph. 1839, 30.— Baird, M. N. A. 1857, 429. Not of Jaroclci. 



"* Etym. Za, augmentative particle, and ttov^, pes. — This veiy pat name was suggested, 

 to the writer by Dr. Gill, who, however, considers the name Meriones to be tenable for 

 this genus. 



