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XIX. On a new Genus of Insectivorous Mammalia. By W.C. L. Martin, Esq., 
F.L.S. 
Communicated February 13th, 1838. 
THE intrinsic value which attaches to the discovery of new modifications of form de- 
pends much on the extent and abruptness of the vacuum which such modifications will 
tend to fill, and on the degree to which their absence has been previously felt. The 
present addition therefore to that particular group of the Insectivora, of which Erinaceus 
may be regarded as the typical genus—a group restricted to the older portions of the 
globe, and more numerously distributed throughout the warmer than the colder lati- 
tudes—cannot I think but be received by naturalists with a certain share of interest. 
On a survey of the Insectivorous section of Mammalia (whether we regard that section 
as an order per se, or as only part of an order), the genera of which it consists mostly 
appear as if isolated from each other, or as so many disjuncta membra, the connecting 
parts between which, and necessary to its harmonious perfection as a whole, having 
either been lost, or having yet to be discovered. 
Between the genus Erinaceus, for example, and that of Centetes, Illig., there has hi- 
therto existed an unfilled interval: this interval, however, has in some measure been 
recently supplied by two genera, both peculiar to Madagascar, of which one has been 
lately characterized by M. Isidore Geoffroy St. Hilaire, under the title Ericulus ; for the 
other I now propose that of Echinops. 
The genus Ericulus includes, as far as hitherto determined, only one species, Ericulus 
nigrescens, Is. Geoff., and which is regarded by M. Blainville as the Tendrac of Buffon. 
The skull and original specimens, from which M. Isidore St. Hilaire took his descrip- 
tion, were carefully examined by me during my recent visit to Paris (the autumn of 
1838). 
With respect to the skull, as in Centetes, and also Echinops (but not Erinaceus), the 
zygomatic arch is incomplete ; its general contour is narrow and elongated, the muzzle 
being produced, almost as much as in Centetes. The dentition of Ericulus is as follows : 
Incisors above 4, disposed laterally in pairs. 
Molars above, on each side 7, of which the two first are false; the true molars, 5 
in number, being transversely elongated. 
Incisors of the lower jaw 4, disposed laterally in pairs. 
Molars, as in the upper jaw, 7 ; 2 false and 5 true. 
M. Isidore St. Hilaire considers the first false molar on each side, in either jaw in 
VOL. I1,—-PART IV. 2. 
