BACCOMYIDiK— DIPODOMYIN.H— DirOD()MY8. 



This second tublc^aii far as it goes, leads to some tangible nnd itrnctical 

 results. Mure specimens would undoubtedly modify the exact figiircH, but 

 would, I think, only confirm the general statement, that there is r dccidi-d 

 diflcrenco in relative length of head and liwly and of toil between specimens 

 fmni the interior and those from the coast region— just as there is in the 

 genus CricetodipuB. This substantiates, in effect, the broad distinction estab- 

 lished by Baird in 1857, though the details given by that author rctiuire 

 qualification.* 



In the animals from the interior, with an average length of nearly 4.50 

 inches, the tail is scarcely or not an inch longer than the body; that is to say, 

 it is about one-fi)urth as long again as the head and body. 



In the coast region specimens, with an average length of less than 4 

 inches, the tail is about 2 inches longer than the iiead and body; that is to 

 say, it is, if anything, i.iore than half as long again as the body. 



The feet do not r resent any very tangible characters. We find them of 

 all sizes, coupled with different extremes of tail length. Nevertheless, '. will 

 be observed that the Cape SL Lucas specimens alone of the coast scries |irc- 

 sent small feet, under 1.50; and that, without these, the coast scries would 

 show a length of foot of l.GO-l.TO, thus correlated with the greater length 

 of tail. 



To these data may be added some others, tending to substantiate a dif- 

 ference between the two forms of the genus. The western animal averages 

 smaller and of more slender build, with larger ears and longer limbs, and 

 especially longer tail. It is darker in color, the prevailing tone being a mouse- 

 brown, overcast with tawny or fulvous. The animal from the interior is larger, 

 and noticeably more stoutly built, with smaller eare and shorter limbs, and 

 particularly shorter tail. It is lighter in color, ))revailing tone being the 



• llanm. N. Am. 1857, p. 409.—" Whirtavar the nunber of qwcks, aU bilberto detoctad Id North 

 Amerin baloog to the two fullowinn aaotioM :— 



** Saolfcm I. Hind foot not eioeadiog IJiO inohaa, nraally appreciably lew ; abont one-tbird tba 

 length of bead and body. Tall vartabna abont 1} tlnaa tba laogth of bead and body iu nature ; rarely 

 exoaedlng 6 Inohaa, never 6^. D. artUI. 



" Seotkm II. Hind foot, IM inohaa, aoaetimea more ; a) waya eooaiderably ezoaading l/>0 ; almoat half 

 aa long aa bead and body In the Siat apeoimaoa. Tail Tertebna l| tlmea the length of bead and body, 

 alwaya exoeadtng 5} Inebaa ; oanally ftom to 7 inebaa. D. pUtlippi, D. mfilU." 



fbe propottlona of body and tall here laid down I Terlfy exactly, thongb the limits of extrami • 

 giveii rtqnira to be enlarged. On the oontrary, the atatementt made reapeetlng the feet do not buM, 

 npon examination of more material. In flwt, the Cape St Loeaa are the iborteat-footed animals of tba 

 whole eerier ; and In one very large Texaa apecimen (dry), not given in the table, tbo foot is almoat > 

 tncbea long. 





A tUAI>i->I.^ .-iv-i^ r- 



