64 INDEX GENERUM MAMMALIUM. 
intermediate forms, but the names alone do not show that J/esonys 
is related both to the jumping rats and Jvws, or that Synaptomys is 
a connectant form between the lemmings and field mice. Aschizo- 
mys (not splitting—in the sense of connecting mouse), which, in a 
somewhat different way, expresses the same idea of connection, does 
not show that it is based on a combination of the characters of 
Microtus and Evotomys.^ Likewise, Orthriomys (early mouse) and 
Phenacomys (deceptive mouse) are not self-explanatory. Orthriomys 
was so called from the fact that it suggests an ancient type inter- 
mediate between Phenacomys and the Microtine Pedomys and Arvi- 
cola; Phenacomys derives its name from the fact that externally it 
is almost indistinguishable from JMerofus. — JTodomys (road mouse), 
refers to the animals habit of making trails, and not, as might be sup- 
posed, to its living along highways. Monachus (monk) is applied to 
the tropical seal, probably because of its more or less solitary habits, 
and Semnopithecus (sacred monkey) to a group of monkeys of India, 
because the type species 1s considered sacred by the Hindus. Less 
clear are such terms as Cryptomys (hidden mouse), Dinomys (terrible 
mouse), and Aenomys (strange mouse), which merely suggest the 
peculiarities of the groups to which they belong without explaining 
them. /%ctinator (comber) and Tamas (steward) convey little idea of 
their appropriateness unless it is known that Pectinator, like Cteno- 
dactylus, has bristles on the hind feet which are supposed to be used 
in dressing the fur, and that Zam7as, the well-known genus of ground 
squirrels, has a habit of laying up stores of food. 
Generic names based on special characters are very numerous. 
They may refer to external characters, such as the skin, hair, head, 
nose, eyes, ears, tail, wings, or feet; to special characters of the teeth, 
skull, vertebra, ribs, or limb bones; or to the soft anatomy. Those 
which owe their origin to characters of the teeth and skull are very 
common, while those based on the soft anatomy are comparatively 
rare. Not only do special parts of mammals suggest names, but a 
wide range of qualities of each part is represented in I 
Thus, characteristics of the skin that give rise to names range from 
narrow (Stenotherzwm) to broad (Megaderma), probably in allusion to 
the size of the flying membranes; those of the hair from soft (Ad- 
rothrix) and woolly (Lagothrix—rabbit hair) to spiny (Lchiothrix) and 
scaly (Lepitherium); those of the nose from allusions to a long nose 
(Nasalis and Oxymycterus) to noseless (Arhinolemur); those of the ears 
and tail from earless (Aotus) and tailless (Anoura) to large eared 
(Macrotis) and feather-tailed (Pteronura); those of limbs from short 
(Brachytarsomys) to long (Megaptera, Macropus). 
The ex xamples just mentioned and some of the designations of teeth 


a Cone the different ways of expressing the same general idea of ‘relationabay 
as exemplified by the following names: Amphicetus, Apalemys, Aschizomys, Dolomys, 
Interodon, Mesomys, Mictomys, Phenacomys, and Synaptomys. 
