

■ilit 





508 



IMOSOOUAPnS OP NORTH AMKIIIO.AN UODBNTrA. 



Tablk l.—Meaturemeiils of eleven apecimeiit o/PKnoGXATiius pknicillaivs. 



•36;ri 

 1333 



i.m 

 lin 



8010 

 433 'a 



tymb 



4a34e 

 493«<i 

 4g34e 

 493 (/ 



LuoaUty. 



San FranciMc MoiiDtaiiiB, Artx . 



(lolonitlo Rlvor, Cal 



Tori Yuma, Cal 



Colorado Desert, Cal — 



Camp Grant, Ariz 



Mojnvo Village, Ariz 



.ilo. 



.do. 

 .do . 

 .do . 

 .do. 



From tip of 11080 to— 



O.SO 



o.ca 



0. C'l 

 (t. 53 

 0. D.-. 



o.uo 



0.63 

 0. 00 



O.DO 

 O.OJ 

 1.00 

 0.00 

 01 

 0.03 

 0.03 

 0.00 



1.00 

 1.10 

 ,1 3J 

 1.10 

 1.10 

 l.SM 

 l.tO. 

 l.CO 



3. CO 

 S.00 

 3 30 

 3. CO 

 3 00 

 2.00 

 3.50 

 3.00 



Tail to end 

 of- 



3.70 

 3.00 

 3.6J 

 3.19 

 3. SO 



3.30 

 4.(0 

 4.33 

 4.30 

 4.41 



3.00 

 4.13 



4.00 

 4.00 

 4. 80 

 4.00 

 5.00 



Lcugthof- 



0.33 

 0.15 

 0.40 

 0.40 

 0.40 

 0.40 

 0.40 



1.00 

 0.00 



a OS 



0.S5 



i.no 



0.03 



o.co 



0.05 

 1.00 

 1.00 



a 



•0 



•s 



e 



p 



m 



'A 



0.30 

 0.33 

 0.35 



o.:io 



0.33 

 0.33 

 0. 33 



Mounted. 

 Diy. 

 ...do. 

 Alcohnlio. 

 ...do. 

 ...do. 

 ... do. 

 ... do. 

 ... do. 

 .. d... 

 ... do 



* MoaflnrameotA of length and of taiI'Vert«b' » f rom WtMxIhoiiHe. In ilN pre&ent Hlatr, the tall, att Wi?ll aa can Ik; JnilKed, 

 Im almat 4.50 long, oxoIumIvo of the terminal pencil, which id half an inch rooru. Tbu dry measnronionta arc not icllablo. 



Taking the last, seven sets of measarements of tlie foregoing table (all 

 made from sexed specimens in the flesh, and taken by the same person,* so 

 that a source of error which lies in different methods of measurement is 

 avoided), we observe that the total length varies from 2.90 to 3.60 — a difl'er- 

 ence of 0.70 — a fair rate of variability for a species. The tail, as usual, varies 

 more than tiie body, or, in this instance, about an inch, whether the vertebrae 

 alone are considered, or the terminal pencil be taken into account. The 

 relatively shortest tail (vertebrae alone) is half an inch longer than the head* 

 and body, or, with the hairs, an inch longer. The relatively longest tail 

 (vertebrae alone) is an inch and a cjuarter longer than the head and body; 

 with the hairs, nearly two inches longer. Much as usual, the rate of relative 

 variability is greater than that of absolute difference in dimension. The soles 

 vary a tenth of an inch in length, or about %\ per cent, of their average length. 

 Other smaller measurements give corresponding results The rates of varia- 

 tion which are determined for the present species are doubtlees equally appli- 

 cable to others of the genus of which I have no alcoholic specimens. 



Upon the supposition that the other allied species described in this paper 

 are really distinct from P. penicillatus, this has a remarkably restricted geo- 

 graphical distribution. So far as I am aware, there are no specimens extant 

 xvt\\\ beyond the limits of the Colorado Valley in that portion of its extent 



*Ia tuuosuriug tails, I tuku as nearly 08 pu^^4iblo tho tiuo k'tiglb, by p1aoin|{ one le;; uf tlio com- 

 osses snugly above tho anus. The length to which .the tail projects beyond tbu.bcdy-iiaii'i, or ita ONlen- 

 rtiblo diinenaion, ia mnaldernbly less. 



-^:i"' 



.. .i.!kUi^'f'.^9&^l;Si:i. 



