I--4 r.ROOKI.YX MrSF.lTM SCIENCE P.Ttli.ETIN 7,. 5. 
I)un"()\\inj4 roiknts, ])a>M'> across llii- moiitli opniint; iiikKt iIr- incisors. 
The minute e\e nu-a>ures 1 . ^j nnii. ni diaineler and i> surrounded 1)\ 
lleshy lids. There is no external ear, llie sini|iK' opening; occurring well 
behind the eye. Tlie external nares are small and set close to.i^ether, 
directly above the base of the incisors. 
The neck is short and thick. The pes and manus of the shcnl legs 
are supplied with still hairs, arising from the sides of the toes. The 
function of these in such a fossorial mammal as Hcterocephahis is cjuite 
obvious, as Thomas ( 1885) has pointed out. The tail is not quite half 
the length of the head and body. 
Perhaps the most remarkable characteristic of this rodent is the 
almost total absence of hair. \'ibrissae are ]irominent about the lips, 
while the chin and throat, as well as the forehead and crown, are with- 
out a vestige of hair. There is a single superciliary vibrissa. Three 
prominent genal vibrissae appear slightly ventrad to a line drawn from the 
e^"e to the ear. These arise from a prominent "wart." Single hairs 
arise from warts here and there about the back and venter, with no ap- 
parent regard to order. The tail contains twenty-two hairs in both 
specimens examined. The integument is exceedingly thin, almost paper- 
like in texture. 
External Measurements of the Two Brooklyn Museum Specimens. 
No. 1394 fern, adult No. 1395 fern, adult 
Head and Body -Z ^7 "im- 84 mm. 
Tail 3''^ mm. 39 mm. 
Hind Foot 20 mm. 20 mm. 
Forearm and Hand 26 mm. 25 mm. 
^[uzzle to Fye 8.8 mm. 9 mm. 
Muzzle to Ear i9o mm. 18.7 mm. 
Eye to Ear 9 m"i. 8 mm. 
Skull. 
The skidl of I Iclcmrcphalus has been ilescribed in some detail by 
the Italian workers, Taioiia and Callaneo. It se^■nl^ hardly necessary 
to dwell at an\ length on this. It seems desirable to list some measure- 
ments, however, as the\ difter slightly from those of other writers. 
Front of nasals to junction of sagittal and lamboidal crest, 15.5 mm.; 
nasals, 6.6 muL by 3 muL ; p.alate length, 1 1 muL ; inlerorbital breadth, 
6 mm. ; combined length of cheek teeth, 3 muL ; intertemporal brea<lth, 
