FASCICULI MALAYENSES 
XXVll 
and so vicious, that passage through the thorny undergrowth is difficult. A 
careful search would probably reveal a large molluscan fauna, always rich 
on limestone, but we were unfortunate in this respect in the dryness of 
the year, which probably caused the majority of the species to disappear into 
the earth. As a member of the ‘ Skeat ’ Expedition one of us took on Bukit 
Tapang several new slugs of the brilliantly coloured and peculiar genus Atopos , as 
well as a very curious snail, Rhiostoma jalorensis , Sykes, which has a shell that 
looks as it it had become partially uncurled and had then been joined together 
by a tubular bridge running between two whorls. Its operculum is also peculiar, 
being very thick and fitting into the shell with a regular spiral screw, probably 
as a protection against the evaporation of moisture, as the species is found, at 
any rate in dry weather, buried in leaf mould, only dead and eroded shells 
occurring on the surface of the ground, where they are very common in certain 
The cave fauna is mainly interesting because it is not a true cave fauna in 
the sense that that of the Mammoth Cave of Kentucky is one, probably because 
the Jalor caves, though they penetrate into the hills for a considerable distance, 
are not uniformly dark throughout, the roof having fallen in in many places 
and so permitted light and moisture to enter, and with them the fauna of the 
outside world. Nevertheless, there are several species found in the darker 
parts of the caves which are, at any rate, very rare elsewhere, notably the so- 
called ‘ moon snake,’ Coluber taeniurus , which, however, is not so common as 
in the caves of Selangor. A very large whip-spider, Stygophrynus cerberus , 
Simon, is extremely abundant on the walls, and a wingless grasshopper belonging 
to the family Stenopelmatidae is even more so. The latter has extremely long 
antennae, one of which is longer and stouter 1 than the other, and the 
whip-spider’s first pair of legs, which it carries crossed over its back, are even 
longer than those of some of its allies, largely taking the place of eyes, though 
these organs, which would appear to be useless to the animal, are well developed 
even as regards their internal structure. Certain Isopods, found under stones 
in the caves, may possibly have degenerate eyes, but they have not yet been 
examined. 
We stayed at Biserat for some weeks in June, July, October, and 
November, 1902, and there obtained a considerable proportion of our anthropo- 
metrical data regarding the Malayo-Siamese, as we have thought it best to call 
the very mixed indigenous population of the Patani States. Our subjects were 
partly prisoners in the jail and partly inhabitants of the neighbouring hamlets. 
We also made large zoological collections in the neighbourhood, and, as 
regards insects, were particularly fortunate because of two events, viz., the 
1. Detailed measurements show that this is usually, but not invariably, the left antenna. — N.A. 
