466 



MONOGRAPHS OP NORTH AMERICAN RODBNTIA. 



name of n Linnasan species of a family distinct from "Zapodiclx, and was also 

 used, by various of the older writers, both specifically and generically. Tims, 

 lacvlvs is a generic t«rm used for the Jerboas by Erxleben (Syst. Nat. 404, 

 No. 38) in 1777, long before Zajms hudsonius had been discovered. It 

 should, therefore, not have been imposed upon any subsequently determined 

 generic type. But even according to the rule, custom or precedent, wliich 

 permits an author who subdivides an old genus to restrict the name of such 

 genus to any one of his new genera he may see fit, Jaculus is still inapplica- 

 ble to the present genus ; for such restriction seems to have been first made 

 by Jarocki,* a Polish naturalist, who, in 1821, employed the term Jaculus for 

 certain pentadactyle species of Dipodida, the name becoming, nt his hands, 

 exactly equivilent to the subsequent Alactnga of Fr. Cuvier (Proc. Zool. 

 Soc. 1836, 141), afterward altered, on account of its barbarous character, 

 to Scirtetes, by Wagner (Arch, fur Naturg. 1841, Bd. i, 119). Clearly, then, 

 if Jaculus is available for any modern genus, it must be for one of the Dipo- 

 dida, and can have nothing to do with the present case. It is as much out of 

 the question, in fact, as either Dipus or Gerbillus. 



So far as I am aware, Jaculus was first used in connection with the pres- 

 ent genus by Wagler, in 1830 (NatUrl. Syst. Amphib. u. s. w.). In this 

 procedure, however, he was followed by no writers of note until A. Wagner.f 

 in his "Gruppirung der Gattungen der Nager in natiirlichen Familien" u. s. w. 

 (Arch, fiir Naturg. 1841, Bd. i, p. 119). used ^^ Jaculus Wagl." as equivalent 

 to, and instead of, Aferiones Cuv. The name, however, did not come into 

 general employ in this connection until 1857, when Professor Baird adopted 

 it in the same sense which Wagler and Wagner had attaclied to it; and his 

 example has been generally followed by the American school. 



2. The term Meriones was invented by Illiger in 1811 (Prod. Syst. 

 Mamm. et Avium, etc p. 82, No. 32), to cover the Old World species "Dipus 



* Jarocki'B work I bavo uot beeu able to coiifiiilt. The title uiul refuroiico, as K>von by A. Milne- 

 Edwnrds, after Brandt, are : — " Zoologia Cayli Zwiertopismo ugoliio. Warazwie, 1821. pi. i, p. 3(1." Hilue- 

 Edwards observes : " Jarocki rdserva lo noiu g^ndrlqiin de Diput anx OerbolseB dont lea pattes post^rieiires 

 sont tridaotylos, et constitua sous lo iioin de Jaoulua iiu Kouveau genre pour lea esp^oea jl pattea poat^ri- 

 eares pentadactyles".— ("titudes pour servir I'histoire de lit Fauno Mnniiualogique de la Cbioe," aj>M(i 

 H. Milne-Edwards's " Kecberches," etc., tome i, pp. 146, 147. 4to, Paris, ia68-74). 



t Saya Professor Wagner (torn. cit. 120) : " Hinsiclitlicb der Beuennnng der amerikaoiacben Spring- 

 DiUnse erinnere icb, duaa ibnen der Name ilerionei, den Kr. Cuvlor auf sie illiertrUgt, nicbt beigelegt 

 werden sollte, indem ihn Illiger an Nager der alten Welt Torgeben bat ; icb bedieue micb daber dea Ton 

 Wagler vorgescblagenen Namens Jaculus." That is to say, Profesaor Wagner objects to M. Cuvier'a 

 transferring lUiger'a Merionet to the American type, without seeming to be nwat« that he is doing 

 the same thing himself, — transferring Jacului tn this type. 



