ALLEN: NEW AFRICAN RODENTS. 445 



enamel fold each (Thomas, 1885). In //. stygius, however, the last 

 (or third) upper molar is much the smallest, rounded in outline, and 

 of about one half the crown area of the tooth next anterior. The 

 first and second molariform teeth are subequal, the former with a 

 well defined sulcus on the inner side opposite the external fold, 

 marking- a slight infolding of the enamel. Of the inferior molariform 

 teeth, the second is the largest; the first and third are of nearly equal 

 length antero-posteriorly, but the former is much the narrower. Each 

 has an external and an internal enamel fold forming thus a rather 

 flattened figure 8 pattern. Parona and Cattaneo show but one 

 sulcus on the external side of the first tooth in H. glaber but their 

 figure is probably incorrect as Thomas states that each has an external 

 and an internal fold. 



The coronoid process of the mandible is short as in H. dunni and 

 Fornaria phiUlpsi. and just reaches a line joining the condyle with the 

 point of the incisor. The incisive foramina are anterior to the maxil- 

 lary bone and their posterior end just reaches the premaxillo-maxillary 

 suture. 



Measurements. — The type was measured when collected, as follows 

 (measurements of H. glaber are added in parentheses) : head and body, 

 98 mm. (95); tail, 47, (39); hind foot, 22 (21.2). 



The skull: occipito-nasal length, 21 (21.5); nasals, 8.3 (7.8); 

 basal length, 20 (21.5); palatal length, 12.6 (13.6); zygomatic width, 

 17.8 (18.3); mastoid width, 12.5 (12); interorbital constriction, 6 

 (6); mandible from condyle to anterior base of incisor, 16.7; upper 

 cheek teeth (alveoli), 3.4; lower cheek teeth (alveoli), 3. 



Remarks. — The single specimen on which this species is based was 

 taken at our camp near Neumann's Boma on the (northern) Guaso 

 Nyiro River, near its northernmost bend. It was captured alive by 

 one of our Swahili boys who found it running about near the camp 

 fire at night. He said that at first it had come near where he was 

 sitting, but he paid no attention until shortly it returned, and he 

 caught it. I have found no mention of such above-ground activity 

 on the part of this animal. When handled it gave vent to its dis- 

 pleasure in a few soft coughs, but did not attempt to bite. This 

 interesting specimen is the first of its genus to be recorded south of 

 Somaliland, and the known range is thus considerably extended to 

 the south and west. The soil along the river valley where it was 

 captured, is light and sandy, and suitable for burrowing. The ele- 

 vation at this point is probably 3000 to 4000 feet, practically at the 

 upper limit of growth of the ivory-nut palms. No other sign of its 



