60 Records of the Indian Museum. [Wor xebie 
are sometimes variable within the limits of a single species, and 
have enabled me to obtain some idea of the extent of this varia- 
tion. 
The number of teeth on the trochanter of the arm is one 
such character, and it sometimes happens that the variation is not 
uniform on the two sides of the body (see text-figs. 1-4, pp. 64, 72, 
74 and 76). 
The structure of the modified joints of the antenniform legs 
of the females of certain species, which Kraepelin has found to 
afford useful specific characters, is almost certainly connected 
with the mating habits of the group (Gravely 1915), p. 522, 
pl. xxiv, figs. 25-26) ; and I have reason to think that it may pos- 
sibly vary, not only according to the degree of maturity of a speci- 
men, but also according to the proximity of the mating period. 
As, however, none of the species in which the structure in question 
is developed occur in the Indian Empire, I have been unable to 
make special collections bearing on this point, and the material at 
present in the Indian Museum is insufficient for its settlement. 
Iwakawa (1908, pp. 287-291, pl. xi, figs. I-4B) has shown 
that the form of the genital segment may vary considerably 
according to age, even when adult characteristics appear to be 
present. 
Kraepelin’s classification is based mainly on the presence or 
absence of a keel between the median and lateral eyes and of a 
tooth on the inner side of the gnathobase of the arm, the number 
of vitreous spots (‘‘ ommatoids”) on the third caudal segment, 
and the form of the tibial apophysis of the male. It is now known, 
however (Gravely, Ig!2a, pp. ror and 106), that the keel between 
the lateral and median eyes, and the tooth on the gnathobase of 
the arm, may either of them be present in the genus Hyfoctonus, 
which Kraepelin believed to be characterized mainly by the ab- 
sence of both. In this connection it is perhaps noteworthy that 
Hypoctonus stoliczkae, the only known species of the genus as 
hitherto defined in which there is a tooth on the gnathobase of the 
arm, occurs in the excessively damp region at the base of the 
Darjeeling hills together with the genus Uvoproctus, which is 
also characterized by the possession of such a tooth; and that the 
remaining genus Labochirus, which is similarly characterized, is 
found in the excessively damp jungles of the Western Ghats and 
of the hills of Ceylon.! There seems, therefore, to be some con- 
nection, at present unaccountable, between the presence of this 
tooth and the degree of moisture characteristic of the natural habi- 
tat of the species possessing ic; and its value as an indication of 
phylogeny is unlikely to be great. 

| That the S. Indian species inhabit excessively damp jungles is an assump- 
tion based on the habits of the Ceylon species. I failed to find any Thelyphonids 
in the damp jungles of Cochin. In Cochin, as in Ceylon, Thelyphonus sepiaris 
lives in comparatively hot dry places. Places suited to the existence of both forms 
are often found in close proximity to one another. 
