A MONOGRAPH OF THE BATS OF NOKTH AMERICA. 95 



is less decided tliaii in V. (dhe-scens. The j;'i;iy color is also (|uite com- 

 monly seeu at the si)ace beneath the loAver jaw as far back as the oral 

 angles. 



A scattered growth of gray hair occupies the ventral aspect of the 

 wing membrane at its upper half from the body to near the elbow. The 

 membranes are ample. The caudal series of vertebra' from the rump 

 to the ankle one-third the distance from the ankle to the non-exserttip. 

 Postcalcaral lobe as a rule well developed and supftorted by a rod de- 

 rived from the calcar. The length of the forearm ranges from 29'""' to 

 33'""'. 



Variations — The variations of V. )iiti(h(s are numerous. They embrace 

 changes in color of the fur, ear, membranes, and the proportions of the 

 thumb, feet, legs, and forearm. Pedomorphic variatiou is extremely 

 common. Before definite conclusions can be reached as to the limita- 

 tions of the group elaborate study of more extensive material will be 

 necessary. 



The species of such distinguished writers as Dr. C. Hart Merriam 

 and Mr. F. W. True can not be lightly put aside, and I am far from be- 

 lieving that the form V. ciliolabrum and V. longicrxis are not additions 

 to our knowledge. I place their descriptions, therefore, not in the Ap- 

 pendix, but in the text under Y. nifidus where they find their proper 

 place as subspecies or as members of groups otherwise aberrant, but 

 not well known. 



The specimens of V. nitidus from Mexico are of a reddish color on 

 the dorsum. The foot, thumb, and tail as in California specimens. The 

 length of the forearm is 28""" to 29"""; the head is two and one-half to 

 three times as long as the foot; the tip of the tail is, as a rule, not exsert, 

 the interfemoral membrane is ample. In a specimen from Jalisco, Mex- 

 ico (American Museum of Natural History), the colors are everywhere 

 darker; so dark, indeed, that at first sight it might be taken for a dis- 

 tinct form. Specimens from California are of four varieties of colora- 

 tion on the dorsum, the chestnut, the olive, the tawny, and the gray; 

 and are thus arranged in the order of the frequency of the several 

 kinds. The tawny and gray are infrequently seen. Darker shades are 

 ai)t to prevail towar<l the northern range of the Pacific slope. 



Oregon and British Columbia have a nitidian bat not found else- 

 where, viz, one in which the basal black of the hair is of a brown shade 

 instead of black, and is thus not in so great contrast with the coh)r of 

 the tip as is the case with the southern specimens. The forearm is 

 3L""" to 36""" long; the head one and one-half times to twice as long as 

 the foot; the tip of the tail is exsert, the thumb measuring from 4"'"' 

 to 5""". 



In a series of four skins collected by Mr. C. P. Streator (Am. Mus.) 

 the dorsum was without the deep basal black, and in its stead an ob- 

 scure shade of deep fawn which passed gradually to the ash or sooty 

 tip. The venter was much more gray than in the southern examples. 



