385 
broader than long, with the lateral margins somewhat convex and 
considerably converging behind; the plate is posteriorly divided into 
two branches by a moderately broad cleft, which is about half as 
long as the plate and rounded at the bottom. The branches are 
broad, obtuse, with a sharp inner angle, and their surface is ador- 
ned with numerous exceedingly small dots. 
Legs. They are robust, short and iucrease rather little in 
length posteiioil). The last pair (fig. 6 b) with the femur nearly 
as long as the trochanter, slightly longer than thick and only a 
little shorter than the tibia, which is scarcely twice as long as 
thick. The tarsus is scarcely one half longer than the tibia. The 
hairs on the coxa and trochanter are biramous with rather siender 
bianches; the seta on the tibia is not half as long as the joint. 
Copulatory Organs (fig. 1 c). Seen from in front they are not 
tw ice as long as broad, rather conical, with the inner margin si- 
nuate and the outer almost straight; the apex is subacute. 
Length. The two largest of my specimens are a somewhat 
contracted male and a similar female; both measured *54 mm. 
Locality. Isl. Ivoh Chang (Gulf of Siam), under stones, 
Jan. 6. and 7. 1900 (Dr. Th. Mortensen leg.). 
Remarks. This species differs widelv from all other forms 
known to me by the aberrant proportions in the length of the hairs 
in the two posterior rows of the head and by a number of features 
in the structure of the anal segment with its setæ and anal plate. 
The name of this very interesting species is chosen in com- 
pliment to Dr. Th. Mortensen, who has collected nine species of 
Pauropus in Siam and besides many other fine Arthropods new to 
science. 
Species 13 — 21. Tliese nine species constitute a rather na¬ 
tural group. The distance between the setæ of the submedian pair 
on the anal segment is often shorter than that between the sub¬ 
median and the intermediate pair; the intermediate setæ are inserted 
in a line at most a little in front of, generally even behind the 
Vidensk. Medd. fra den naturh. Foren. 1901. 25 
