Merriam — A New Mountain Sheep from Sonora, Mexico. 131 



Characters. — Size smallest of the known mountain sheep — a dwarf de- 

 pauperate desert species, with small skull, relatively large teeth, and 

 small compactly incurved horns ; hoofs of essentially the same size as in 

 gaiUardi. 



Color. — Pelage of type specimen much worn and faded; rump stripe 

 narrow; general color of body and legs drab brown, much paler than 

 November and December specimens of gaiUardi from the neighboring 

 Gila Range. Compared with these, the face is apparently grayer, but 

 owing to the fact that the skin of the head is turned inside out, and very 

 hard and dry (not having yet been tanned), the colors of the head and 

 face can not be satisfactorily made out. The rump stripe is much nar- 

 rower than in gaiUardi. There is a small elongate patch of new pelage 

 on the median line where the neck joins the shoulders. Its color is 

 almost slate gray (of Ridgway) — very different from the color of the same 

 part in gaiUardi. 



Cranial characters. — Size small; frontal region markedly dished, rising 

 strongly from facial plane to summit between horns ; face and nasals 

 rather short ; nasals broadest in middle third ; orbits not strongly out- 

 standing; palatal bridge long anteroposteriorly for size of skull. Com- 

 pared with adult rams of gaiUardi from the neighboring Gila, Tule, and 

 Pinacate Ranges: Skull very much smaller; frontal region more strongly 

 dished ; nasals reaching farther anteriorly and less broadly flattened in 

 middle part; bullae larger; palatine bridge actually as broad or broader, 

 relatively much broader; postpalatal notch shorter; molars essentially 

 the same size, but relatively much larger. Length of molar series ex- 

 ceeds distance from front of series to front of premaxillae by fully % 

 inch, while in gaiUardi rams the two lengths are equal. 



Compared with an adult female gaiUardi (No. 202971) from Tule 

 Mountains, Sonora, the skull of the female sheldoni No. 210586 from 

 El Rosario differs in the following particulars : Size conspicuously smaller ; 

 orbital rings less outstanding; bullae slightly larger; palatine bridge de- 

 cidedly larger (about 10 mm. longer anteroposteriorly), less deeply cut 

 by postpalatal notch, and reaching anteriorly nearly to posterior plane 

 of 1st molar [in old 9 gaiUardi reaching only to posterior plane of 2d 

 molar] ; posterior nares 10 mm. shorter; jugal arm of squamosal shorter; 

 ramus of jaw about 15 mm. shorter, deeply bellied under posterior molars 

 [in gaiUardi nearly straight] ; angle more broadly rounded [in gaiUardi 

 more squarely angular] ; molariform teeth inserted more posteriorly and 

 much less massive, but series of essentially same length ; 3d lower pre- 

 molar with outer sulcus much deeper, and posterior column narrower. 

 Some of the above differences may be due to age, the female skull of 

 sheldoni, while fully adult, being less old than the female gaiUardi. 



Flesh measurements of adult ram (the type) taken by Charles Sheldon: 

 Total length including tail, under 52 inches; tail, SJ^ in.; height at 

 shoulders, under 30 in. ; hind foot, 14 in. Horns (5 rings) : Circumfer- 

 ence at base (fresh), 13>^ in. [now shrunken to 12%] ; length, 29x\ [now 

 293^] ; tip to tip, 12^; widest outside measurement, 18. 



