84 Mr. R. V. Chamberlin on new 
one and on each side of this a narrower and more acute 
process. 
The sternal processes erect, long, and acute. 
Gonopods of male nearly as in H. hosci (Poc.). 
Length (male) about 70 mm.; width 11°5 mm. 
Locality.— Borneo (H. W. Smith). 
Type, Mus. Comp. Zool. (No. 4678). 
Platyrrhacus attenuatior, sp. n. 
This species resembles P. vittatus (Poc.) in having a 
coutinuous median longitudinal pale stripe along the 
dorsum ; but the general colour is darker, chocolate to 
brownish black, and the keels at their borders are paler, like 
the median stripe; prozonites darker, more blackish. The 
median pale stripe may be distinct only on the prozonites. 
The species is characterized also in having the body 
(inclusive of the keels) widest at the third or fourth 
segment, from where it narrows gradually but continuously 
to the caudal end. Prozonites densely, finely, and evenly 
shagreened. Metazonites densely granular ; the tubercles of 
the transverse rows small, those of the caudal row the most 
distinct. Collum much wider than head. Head densely 
granular. Vertigial furrow deep. Across lower part of 
clypeus an upper transverse row of four and a lower rew of 
six, and just above labral margin a row of more numerous 
and smaller brushes or pencils of seta, each group arising 
from a foveola. The anterior edge of the collum is mesally 
straight, at the ends very slightly produced forward. Behind 
the anterior row of tubercles a deep transverse furrow 
widening and deepening at each end into a pit-like depression. 
Anterior portion of lateral margin crenate, with three 
rounded crenations inclusive of the one at the angle. 
The anterior edge of the keels of the second segment is 
also turned up, while the keel just behind it shows a wide 
pit-lhke depression. The lateral margin of the first five 
keels is laterally wavy ; on succeeding keels the elevations 
become more and more pronounced and tooth-like; the teeth 
in the posterior region large, triangular, mostly three in 
number exclusive of those at the angles, but the number 
on the fifteenth and sixteenth plates is four or five and on 
the seventeenth and eighteenth five or six. Anterior 
and posterior edges wholly smooth. Posterior angles not 
produced into spiniform processes, though the nineteenth 
keels are bent back markedly and are rounded at the caudal 
ends. Anterior pore areas twice their diameter from the 
