371 
seta on the tibia is balf as long as the joint. Femur and tibia 
are partially delicately pubescent. 
Copulatory Organs (fig. 6 c). Seen from the side they are 
moderately thick and almost regularly conical, distally the margins 
are yet somewhat convex; the apex is produced and acute, the seta 
terminal. 
Length. An extended male measures *8 mm., a somewhat 
contracted female -58 mm. 
Locality. Isl. Koh C hang (Gulf of Si am), Jan. 6. and 7. 
1900, under stones (Dr. Tb. Mortensen leg.). 
Remarks. By the strong process from the tergum of the 
anal segment, the length of its dorsal setæ and the extreme length 
of the pubescence on the very thick tactile setæ of the fifth pair 
this species is easily distinguished from all others known to me. 
The anal plate is to a certain degree similar to that in P. vul- 
garis, Avhich in most other features is very distant. 
Species 7 11. These iive species constitute a rather natural 
group. The distance between the setæ of the submedian pair on 
the an'al segment is as in P. Huxleyi at least somewhat longer 
than that between the submedian and the intermediate pair; the 
intermediate setæ are inserted essentially in front of and rather or 
^ er} neai the lateral one; these are long or very long, more 
than half as long as the breadth of the segment and always longer 
than the posterior ventral setæ , and these characters separate this 
group from the last one (species 13—21). The styli are short and 
often thick; the anal plate has no posterior angles and only two 
branches. The sternum of the anal segment has three pairs of setæ, 
and the anterior pair is short. The legs are generally of moderate 
length and never very short. 
7. P aur opus argentinensis n. sp. 
PI. III, fig. 2 a—2 g. 
Material. Six adult specimens, males and females, rather well 
preserved, but all more or less contracted. 
24 * 
