632 MURIDAE—MUS 
distribution in southern Asia and in Africa, and having no near 
relationship with any other genus, except the Indian Legga- 
dilla, which may be regarded as an offshoot. The genus 
betrays a high degree of specialisation, and as regards its 
dental characters it undoubtedly stands on a loftier plane than 
does any of the other members of the sub-family dealt with in 
this work. 
Externally this genus does not differ noticeably from 
Epimys, but all the known species of A/us are of small size. 
The females have ten mamma, arranged in three pectoral and 
two inguinal pairs. 
In the skull the brain-case is rather small and depressed ; 
there are no interorbital beads (present in Leggadt//a), and 
the temporal ridges of the brain-case are very feebly developed ; 
the zygomatic arches are relatively strong, particularly as 
regards their anterior maxillary portions, and there is a small 
peg-like process on the outer side of each maxilla below and 
just in front of the lower zygomatic root, which serves for the 
attachment of the tendon of the anterior part of the masseter 
lateralis muscle. 
In the dentition the upper incisors are strongly curved, 
terminating behind in the maxilla between #' and the maxillo- 
premaxillary suture. The disc of wear is peculiar, there being 
a well-marked notch on the outer side just behind the junction 
of the white dentine with the yellow enamel. Winge explains 
this feature by supposing the dentine to be harder at the 
postero-external corner of the tooth than elsewhere; Miller, on 
the other hand, attributes it to the angle at which the teeth 
are set. We are not able to find any appreciable difference 
between A/us and “pzmys as regards the “set” of the incisors, 
and would attribute the notch rather to the increased strength 
and peculiar mode of action of the masseteres laterales muscles, 
which have induced several much greater modifications in the 
structure of the cheek-teeth as well as in the skull itself. 
The lower incisors terminate behind, near the bases of the 
condylar processes, their ends producing rather well-marked 
humps on the outer surfaces of the mandible. 
Cheek-teeth (PI. XXVIII., Fig. 10):—In this genus m+ 
1 
are relatively large, being as long as or longer than m=} 
