1875.] MR. E.R. ALSTON ON THE GENUS ANOMALURUS. 95 
Galeopithecus, founded on the compression of the toes and claws, 
seems too fanciful to require discussion, though by a curious co- 
incidence the ceca of the two animals are somewhat similar in 
appearauce, 
What may have been the causes of the wonderful modification of 
the alimentary system and the subsidiary parts of the skull in 
Anomalurus is more doubtful. The facts seem to point to the effect 
of a more dry and innutritious diet. Beyond Temminck’s statement 
that “ils se nourrissent de fruits,” nothing has been recorded of the 
food of the Anomalures; and the contents of the stomachs of the 
specimens 1 have examined were unfortunately too well digested to 
yield much information. That of 4. pelii, however, contained a 
quantity of long vegetable fibres, which seems not unfavourable to 
the idea that they may live principally either on dry and stringy 
fruit or on leaves, | 
A further question, and one perhaps incapable of a satisfactory 
solution, remains. Is Anomalurus more closely allied to Preromys 
and Sciuropterus than to the non-volant genera of the family? or 
are their resemblances an instance of the independent origin of 
similar structures? The development of a flying-expansion in itself 
naturally points to the former view, while the remarkable difference 
in the attachment and course of its expanding cartilage seems to be 
in favour of the latter. 
The geographical distribution of the two groups is worthy of note. 
As for as we know at present, the Anomalures appear to be confined 
to a limited region of West Africa, extending from the equator to 
about 15° north latitude, whereas no species either of Pteromys or 
Seiuropterus seems ever to have been met with in any part of the 
/Kthiopian region. 
If the above views are correct the systematic position of the 
Anomalures is settled, and their rank will merely depend on the 
higher or lower value given to the whole sciurine group of ro- 
dents. If the latter is regarded as a family, then the <Ano- 
malurine will be a subfamily of Sciuride; if as a separate section 
of the order, the Anemaluride will form one of the constituent 
families of the Sciuromorpha. In either case the characters will 
be the same as those proposed by Mr. Waterhouse for the only 
known genus. 
I now conclude with the synonymy, characters, and habitats of 
the known species of the genus. 
SPECIES. 
1. ANOMALURUS FRASERI. 
1842. Anomalurus fraseri, Waterhouse, P. Z. S. 1842, p. 124; 
Ann. & Mag. Nat. Hist. x. p. 201. 
1842. Pteromys derbianus, Gray, Ann. & Mag. Nat. Hist. x. 
p- 262. 
1843. Anomulurus derbianus, Gray, List Mamm. Brit. Mus. 
p- 133. 
