442 



REPORT OF STATE GEOLOGIST. 



enabling the student to identify mammals with the smallest possible 

 labor. Where a genus is represented by more than one species in 

 the State, keys to the species will be found under the genus. Ex- 

 ternal and easily distinguished characters have been used as far as 

 possible, although in some cases skulls and teeth are essential and 

 they are always desirable in establishing the identity of any mam- 

 mal. (See figures 2 and 3 for parts of the skull.) 



KEY TO ORDERS, FAMILIES AND GENERA. 

 (Note. — I = incisor teeth; C = canines; Pm = premolars; M = molars. See figures 2 and 3.) 



A. Fore limb modified into a wing with an elastic membrane stretched be- 

 tween the long digits and also between the arm and the body. (Bats.) 



Order CHIROPTERA and Family Vespertilionidae, p. 616 

 B. Ears more than one incli long, partly united in front of the head. 



Genus Corynorhinus, p. 617 

 BB. Ears considerably less than one inch long, widely separated in front. 

 C. Membrane between the hind legs about as thickly furred on top as 

 the body. Genus Lasiurus, p. 633 



CC. Membrane between hind legs so scantily furred that the skin is 

 distinctly visible. 

 D. Fur blackish with whitish tips that give it a frosted appearance 

 (teeth on each side, I, |; C, |; Pm, f ; M, f). 



Genus Lasionyctcris , p. 626 

 DD. Fur without frosting; teeth not as above. 



E. Size very small; color yellowish brown (teeth, I, I; C, 



Pm, I; M, |.) Genus Pipistrellus, p. 629 



EE. Color darker brown; teeth different. 



F. Size large (total length more than four inches) teeth, 

 I, I; C, j; Pm, ^; M, |. Genus Eptesicus, p. 631 



FF. Size smaller; total length less than 4 inches. 

 G. Upper incisors 4; common cave species. 



Genus Myotis, p. 620 

 GG. Upper incisors 2; rare or perhaps absent from our 

 fauna. Genus Nycticeius, Appendix, p. 648 



AA. Both pairs of limbs adapted for walking or running; no wings. 



B. Inner toe of hind foot widely separated from the rest, like a thumb 

 and without a sharp claw; teats of female opening inside a pouch on 

 the abdomen; upper incisors ten. (Opossum). 



Subclass METATIIIORIA, Order JWARSUPIALIA and Family Didel- 

 phidae. Genus I)i(lel))}i is, p. 448 



BB. Hind feet not as above; no i)ouch bcntnith the abdonuMi; u|){)er in- 

 cisors less than ten. Subclass L^utiieria.* 

 C. Feet all terminating in lioofs (bison and (k'cr). 



Order UngULATA, p. 451 

 I). Horns hollow, perinanent and growing throughout life. 



Family Boviddc, Geinis Bison, p. 4r)2 



♦The bats, at the Ijotciiininj; of the ko.v, also belong (o the I'lui ii loin a. 



