166 BULLETIN 144, UNITED STATES NATIONAL MUSEUM 



(ratio in 16 specimens, 43.4). The calcar is long and slender, equal- 

 ling or exceeding the free border of the interfemoral, and ends in 

 a small projecting lobule. Its edge has a prominent keel, that rises 

 with gentle slope at about the length of the metatarsus from the 

 foot. The length of the leg and foot from knee to end of extended 

 claws is usually about 21 to 23.5 mm. 



Fur and color. — The pelage is even more full and silky than in 

 Myotis calif omicus^ the tips of the long hairs toning on flaxen or 

 yellow rather than on the dull chestnut of the latter. The most 

 striking differences between the two are: (1) the frequently bur- 

 nished tips of the hairs in Myotis subulaius as contrasted with the 

 usually dull lusterless pelage of M. calif ornicus^ and (2) the black 

 face and ears of M. subulatus giving a masked appearance, whereas 

 in M. calif ornicus^ although the lips and ears may be dark brown 

 they do not ordinarily show out in sharp contrast with the rest 

 of the pelage. The wing membranes of M. subulatvs are usually 

 more blackish than those of M. coHifornicus. 



Skull. — The skull is delicate and slender, proportioned much as in 

 Myotis calif omicics, but it is slightly longer and broader (compare 

 pi. 1, p. 7, figs. 15 and 14). It differs notably from that of M. cali- 

 f amicus in the breadth and flatness of the brain case, so that viewed 

 from behind the occiput (pi. 1, p. 7, fig. 11) appears to be less elevated 

 than in the smaller animal, and the summit is actually broader 

 and more flat ; there is no abrupt step from rostrum to forehead, but 

 a very gradual upward slope. 



On account of the unusual cranial breadth the temporal ridges 

 do not meet until in adult life ; they first come together well forward 

 of the occiput, cutting off an isosceles triangle with long tapering 

 point and sometimes forming a low but sharply defined sagittal 

 crest. The base of the triangle projects back with convex outline 

 slightly behind the level of the lambdoid crests. 



Teeth. — In form the teeth do not differ appreciably from those 

 of Myotis californicus. The crown area of the upper molars is, 

 however, appreciably greater than in the small races of M. cali- 

 fornicus occurring north of southern Mexico. Taking specimens 

 of the two species from localities in the United States it is seen that 

 the crown of rn? in M. californicus usually measures 1.15 to 1.25 by 

 1.45 to 1.60, while in M. suhulatus the usual dimensions are 1.25 to 

 1.35 by 1.60 to 1.85, a difference which soon becomes obvious to the 

 eye even without direct comparison. 



Remarks. — This bat, the animal originally described by Say in 

 1823 as Vespertilio suhulatus (not the Vespertilio suhulatus of Har- 

 rison Allen, 1864, and the Myotis subulatus of recent authors), seems 

 to be uncommon in the eastern United States, though of general 

 distribution. It has usually been confused with Myotis lucifugus 



