78 Merriam — Descriptions of Ten New Kangaroo Rats. 



broadly ami S(niarcly sprcadiiii,' maxillary routs of zyjiomata, broad and 

 strongly aiit,d(,'(l (almost liookcd) maxillary arclics, and loii.ir nasals. Com- 

 ])an'd witli nevadenslx and ullrdloidt's (with which it a,<:i\'cs most closely) : 

 fronto|iarit>tal shit'ld l)road('r; skull l)r(iadcr across mastnids; maxillary 

 rnots of zy<inmata more broadly and S(|narcly s]in'a<lin.u; mastoids some- 

 what smaller (narrower) thoniih posterior se^nnent is fnlly intlated; nasals 

 lon.ix, as in ucntdfitsls — decidedly loim-ei- than in intnitnidt's. 



Measarementa. — Tyi)e six'cimen, ( c? ad.): total lenjjtli, 240; tail verte- 

 bnp, 140; bind foot, .">7. Sknll: ;^reatest len<jtb, .'U."); occipito-nasal length, 

 32.5; mastoid breadth, 22.."); maxillary breadth, 20. 



Perodipus stephensi sp. nov. 



Typi' from San Jacinto A'alley, Riverside Comity, Calif., No. ifff d^ 

 ad., INIerriam Collection. (!olU'cted Nov. 27, ISSo, l)y Frank Stephens. 



('hdi-dctfrx. — \Vry distinct from all other species except s/rrfttori and 

 IKdHtiiiii/liiiiis both of which it resembles in the <jeneral scjnarish form of 

 the sknll. Ears moderate, abont as in jiniKimiiithnix — smaller than in 

 agills. 



Color. — Similar to p(iu<iinlii.liini>i but darkt'r. 



Cranial fharacters. — General form of skull "squarish" as in xlri-atoi'i 

 iiiu\pa)iaiii!Hliiin.'<; frontoparietal shield broadly " S(|uarish " (contrasted 

 with wed,t!;e-sliaped ) ; maxillary root of zyifomata broadly and s(piarely 

 spreading; maxillary arch broad and strongly angled. Compared witli 

 panamltdriius (probably its nearest I't'lative) the skull is slightly smaller; 

 the interparietal area and basioccipital decidedly narrower; rostrum and 

 nasals slightly smaller and mon' slender; mastoid biill;e slightly fuller 

 and deeper (best seen from behind). 



Compared with sU-eatori (which it rescind >les surprisingly in general 

 form anil si/.e) the interparietal area axcrages nan-ower; outer angU' of 

 l)arietal more produced, giving the cranial shield greatt'i' breadth poster- 

 iorly; mastoid bulla' fnlK'r and deejx'r vertically (liestseen from behind); 

 incisors weakt-r. 



Perodipus morroensis sp. nov. 



Type from Morro, San Luis Obispo Co., Calif., No. ^IIH $ ad., U. S. 

 National jNIuseum, Biological Survey Collection. Collected Nov. II, 1891, 

 by E. W. Nelson. Orig. No. \\M. 



Charucleri^. — A ilark, highly colored form resendtling K'niiuhinn exter- 

 nally excejit that the ear is smaller and nose bar blacker. I<'arsdark; 

 nose spot jet black and continuous, with black whisker p:dch(~; back 

 darkest, with faint olixaceous tinge ; front of face (eyes to nose) gri//,led 

 ])ntty and dusky, much paler than top of head and back; thigh i)atclies 

 mixed with dusky and becoming bla'ck on aid<le-i. Similar in general to 

 agilla but ears somewhat smaller; color slightly darker, ])articularly on 

 sides of head below ears and on end of nose ( w hich is black and connects 

 with whisker ])atches, thus forming a black bar across front of face) ; 

 thigh patch ilarker ami passing i)osti'riorly into vsooty black. 



