598 PROFESSOR PETERS ON THE GENUS PECTINATOR. 
systematic position of the latter itself have not, until now, been quite settled. In fact, 
there exists hardly any other genus of Rodents of which the systematic position has 
given rise to so many difficulties and which requires a more careful examination than 
these very curious and interesting genera of continental Africa. 
Not taking into consideration the opinions of Dr. Gray’ and Mr. Yarrell?, who placed 
Ctenodactylus along with the Arvicole, because at that time attention had not been 
called to the importance of craniological characters for a more natural arrangement of 
the Rodents, there exist at least four different systematic views to be mentioned. 
A. Wagner® places Ctenodactylus, together with Echinomys &c., in his family of 
Psammoryctina; Professor Gervais‘ unites them with the Jerboas (Dipodes); Brandt’, 
in his classical essay on the craniological characters of the Rodents, comes, after a careful 
examination of the skull, to the conclusion that the group of the Ctenodactyli belongs 
to the subfamily Octodontes (Octodontina, Waterhouse); and to Mr. Blyth, as before 
mentioned, they seem to form a peculiar group, most nearly allied to the Chinchillina. 
Mr. Waterhouse does not mention the Ctenodactyli, in his excellent work on the 
Rodents, amongst the Hystricide ; but in a table of the geographical distribution of the 
Rodents’ he places the “Section 3. Cfenodactylina” in his family Muride (composed 
of Myoxina, Dipodina, Ctenodactylina, and Murina) between the Dipodina and Murina. 
The collection of Mr. Jesse contains five specimens, in a more or less good state, pre- 
served in alcohol, besides an imperfect skeleton and a tolerably good skin’. For com- 
parison, the Berlin Museum has of Ctenodactylus two stuffed specimens, one in alcohol, 
and a separate skull. 
External Characters. 
According to all accounts the appearance and behaviour of the little animal in its 
natural state is very like that of a Squirrel, it being very lively in its movements, and 
generally carrying its bushy tail aloft®. However, in its somewhat clumsy form of 
body, less prominent eyes and ears, and shorter limbs, as also in size, it more resembles 
a Guinea-pig. 
The ears are rounded, as broad as high, externally well clothed with soft hair, 
1 Spicilegia Zoologica (1830), p. 10; List of Mammalia, 1843, p. 117. 
? Proc. Comm. Zool. Soc. Lond. i. 1831, p. 48. 
5 Archiy fiir Naturgeschichte, 1842, i. p. 1; Schreber, Siiugethiere, Suppl. iii. 1843, p. 353. 
‘ D’Orbigny, Dict. d’Hist. Nat. 1848, xi., Rongeurs, p. 203; Hist. Nat. d. Mammiféres, 1854, i. p. 373. 
5 Untersuchungen iiber die craniologischen Entwickelungsstufen der Nager, 1854, p. 259. 
5 The Physical Atlas of Natural Phenomena, pl. 28 (communicated by the author). 
7 The bottle sent to me with the specimens contained besides:—1, a specimen of Crocidura sericea, 
Sundeyall, from Waliko, near the river Anseba; 2, Mus musculus, L., from Zoulla camp; 3, Mus gentilis, 
Brants, from the sand-plains of Zoulla. 
® According to Mr. Jesse and Mr. Blanford (Observations on the Geology and Zoology of Abyssinia, Lond. 
1870, p- 281). Dr. y. Heuglin, on the contrary, says that, when running, the Pectinator keeps its tail in a 
horizontal position, and that only when sitting is this organ erect and applied to its back. 
