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Rey. F, W. Hope, which that gentleman many months ago, in the 
most handsome manner, placed entirely at my control for the pur- 
pose of describing, I discovered a third species, brought to this 
country by the late Rev. Lansdowne Guilding, from the island of 
St. Vincent, which I immediately recognized as a new genus; and 
on examining the unarranged specimens of Myriapoda in the coliec- 
tions of the British Museum, which the head of the zoological depart- 
ment, J. E. Gray, Esq., has kindly permitted me to describe and 
arrange, I have since found two other species, both new to science, 
one of which was brought from India by — Elliot, Esq., but the lo- 
cality of the other is unknown. ‘The genus I am now about to pro- 
pose will thus include five species, agreeing most accurately in their 
generic characters. They are all of them foreign to this country. 
The only native species which at all approaches to Mecistocephalus 
is the Geophilus longicornis of Leach, supposed by M. Gervais to be 
Scolopendra electrica of Linnzeus, which constitutes Leach’s second 
section of Geophilus. This I propose to separate as a distinct sub- 
genus, by the name of Necrophlwophagus, although its characters are 
not so distinctly marked as in the preceding. ‘The name proposed 
for it is derived from its being mostly found under rotten wood, or 
under the rotten bark of trees. 
‘* Before I proceed to characterize these genera, it may be well to 
remark, that the construction of the head in these, as compared with 
the other Geophili and the Scolopendre, seems to throw much light 
on the number of parts which are included in this division of the 
body in the higher Articulata, and on the manner in which these 
parts are united; and although I do not intend on the present occa- 
sion to enter on the consideration of these structures, which I pro- 
pose to do hereafter, it is necessary to state that I regard the head 
of the Chilopoda as formed of two compound moveable portions, the 
anterior of which, bearing the antennz, I shall designate the frontal 
segment ; and the posterior, which gives attachment to the large forci- 
pated foot-jaws, which I regard as the analogues of the mandibles of 
insects, I shall call the basilar segment. Posterior to these there is 
a third part, which, although perfectly distinct in all the Geophilide, 
is united to the basilar in the Scolopendre and higher genera of this 
order, forming a kind of cephalo-thorax or cephalo-prothorax.. This 
I shall consider the second or sub-basilar segment. 
“It is on characters derived from these parts that I now propose 
to establish the genera.” 
Class MYRIAPODA. 
Order 1. Cu1nopopa. 
Family Groruitip#, Leach, 
Section A. Geophili mazillares, Gervais. 
Genus Mecistocephalus*, Newport. 
Characters—Frontal segment very narrow, elongated, four-sided, 
more than twice as long as broad, antenne inserted on the frontal 
* From “yxioros, longest, and xePeay, head. 
