6o ' NELSON 



below at base, grizzled brownish gray, rest of lower surface with a 

 broad median band of grizzled rusty yellowish, broadly bordered with 

 black and narrowly edged with white. Hair on back black with broad 

 median ring of rusty or buffy yellowish. 



Variation. — Two of the Manzanillo specimens resemble the type 

 and are very different from typical collicei. Three others are grayer 

 than the type, or less strongly shaded with yellowish on back, but may 

 be distinguished from collicei by the rusty ears, more yellowish suf- 

 fusion on nuchal area, and heavier wash of black on rump. On three 

 of the specimens the median line on lower side of tail is grizzled yel- 

 lowish rusty ; on two others it is grizzled gray with a yellowish suf- 

 fusion. Specimens from Ixtapa, Las Palmas, Mascota, and San 

 Sebastian are intermediate but are more like 7iuchalis than like true 

 collicei. Compared with typical collia:i all of the twelve specimens 

 from these localities have the ears more yellowish or rusty ; the nuchal 

 area yellower than rest of back; the crown, lumbar region and rump 

 more heavily washed with black ; the median line on lower surface of 

 tail grizzled rusty rufous on two specimens, and suffused with a paler 

 shade of same on a number of others ; pelage coarser and harsher, 

 with grizzling on back consequently coarser. 



Measure?ne7its. — Average of five adults from type locality : total 

 length 530; tail vertebrae 274.8; hind foot 68. 4. 



Cranial characters. — Premolars \. Skull similar to that of typical 

 collicei but larger, with proportionately larger audital bullae and rather 

 broader, heavier jugals. Five adult skulls from the type locality aver- 

 age : basal length 52.3; palatal length 27.6; interorbital breadth 

 206; zygomatic breadth 35.9; length of upper molar series ir. 4. 



General notes. — This form is characterized mainly by the increased 

 rustiness on the head, body, and under side of tail. There is a pro- 

 gressive increase in the amount of this color southward from San Bias 

 to Manzanillo. 



Specimens examined. — Seventeen: 5 from Manzanillo, Colima ; 12 

 (all intermediate) from San Sebastian, Mascota, Las Palmas and 

 Ixtapa, Jalisco. 



SCIURUS SINALOENSIS sp. nov. Sinaloa Squirrel. 



Type from Mazatlan, Sinaloa, Mexico, no. 13753, $ ad., Ameri- 

 can Museum of Natural History, N. Y. Collected Jan. 27, 1897, by 

 P. O. Simons. 



Distribution. — Arid tropical parts of southern and central Sinaloa 

 (below 2500 feet). 



