384 



LONCHERES. 



molars with one internal and three external loops; lower molars with 

 one external and two internal loops ; mandible broad with conspicuous 

 bead on inferior outline, the angle prolonged into a lengthened 

 delicate spur; condyle broad, rounded at extremity; coronoid process 

 short, pointed; symphyseal portion narrow, lower outline V-shaped. 



403. labilis (Lonchcrcs} , Bangs, Amer. Nat., xxxv, 1901, p. 638. 

 GLIDING SPINY RAT. 



Type locality. San Miguel Island, Bay of Panama. 



Genl. Char. Pelage long, stiff; spines wanting. 



FIG. LI. LONCHERES LABILIS. GLIDING SPINY RAT. 



Color. Top of head, nose, and cheeks mixed black and yellowish; 

 patch of yellowish white at base of whiskers, also one above eye and 

 behind ear; rest of upper parts bright ferrugineous, varied with black 

 in certain specimens; chin grayish white; under parts buff or ferru- 

 gineous in some individuals these colors show in patches; upper 

 surface of hands and feet yellowish brown; nails white; tail at base 

 like body, then black, tipped sometimes with yellowish white; ears 

 blackish, nearly naked. 



Measurements. Total length, 420-540; tail vertebrae, 175-240; 

 hind foot, 42-48; ear from notch, 14-16. Skull: basal length, 47.8; 

 occipito-nasal length, 56.6; zygomatic width, 27.4;' mastoid width, 

 22.4; interorbital constriction, 12; length of nasals, 16; width of 

 nasals, 7.2; palatal length, to palatal notch, 21.2; to end of pterygoid, 

 36.4; upper tooth row, 13; length of single half mandible, 34; lower 

 tooth row, 13.2. 



The next is a comparatively large genus of moderate sized Spiny 

 Rats. One curious characteristic of these animals is the tendency to 

 lose their tails, the separation taking place at the fifth caudal ver- 



