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Or 
SOME POINTS IN THE ANATOMY OF THE PLATYDESMID. 
oa 
On Some Points in the Anatomy of the 
Platydesmide. 
By 
F. G. Sinclair, F.L.S. 
With Plate 29. 
In 1901 I received a small amount of material which 
enabled me to make out a little of the anatomy of the species 
of Platydesmus, which I described in my paper on the 
Myriapods of the Skeat Expedition as Platydesmus 
kelantanicus. 
The material was not enough to enable me to make out 
many points, and so was laid aside till 1903 when Dr. H. 
Gadow brought me back a quantity of P. mexicanus from 
Mexico, sufficient to allow me to proceed with my investiga- 
tions. Iam glad to have this opportunity of thanking him 
for his kindness. 
The general appearance of P. mexicanus is given in 
Humbert and Saussure’s work, “ Etudes sur les Myriapodes,” 
and of P. kelantanicus in my own paper, so it will not be 
necessary to describe them again here. 
The first point that strikes one in examining this animal is 
the extreme smallness of the head in comparison with the rest 
of the body. It is almost concealed beneath the tergal plate 
of the neck. In the next place the similarity of the individual 
segments attract one’s notice; there does not seem to be the 
same amount of specialisation of regions in the neighbourhood 
of the thorax that one finds in most Myriapods. This appear- 
ance is, however, to a great extent, deceptive, as closer 
