I. 
A SYNOPSIS OF MALAYAN PLATYRRH ACID^, 
A recent opportunity of examining for the second time some of 
the types of species of this group in the Berlin Museum has confirmed 
the opinion that several genera have hitherto been confused under 
the names Stenonia, Platyrrhacus, and Acanthodesmus. As a begin- 
ning toward the elucidation of the group the following synopsis of 
generic types studied by me is here offered. Drawings and extended 
descriptions are in preparation. 
Very lar^e (90-130 mm. in length) ; dorsum very slightly granular, coriace- 
ous, or smooth, except that there are three more or less distinct transverse 
rows of small tubercles ; lateral margin of carinse with several coarse teeth ; 
first segment broadest in front, the anterior corners produced and rounded : 
Genus Phyodesmus, type Ph. pictus (Peters), Borneo. 
Small to large (not exceeding go mm.); dorsum densely granular, or the 
lateral carinae with margins subentire, erose, or deeply bifid ; first segment 
subelliptic, broadest at or behind the middle, the anterior corners not de- 
veloped. 
Sterna with two pairs of long, sharp spines, of which the anterior pair is di- 
rected cephalad, the posterior caudad ; carinse laterally margined outside the 
pore : Genus Phractodesmus, type Phr. subvittatus (Peters), Linga. 
Sterna unarmed, or with four more or less distinct, short, conic spines all di- 
rected ventrad or slightly caudad ; carinse laterally immarginate, or the pore 
included in the margin. ........... 
Copulatory legs unbranched, extended into a long, coiled process : Genus 
Derodesmus, type D . flai^elUfer, sp, ??., Ternate. 
Copulatory legs with two or three distinct prongs. ..... 
Dorsum with three conspicuous and equal transverse rows of prominent, 
oval, smooth, tubercles ; carinse laterally strongly margined ; margin smooth 
and prominent, below with a large rounded tooth ; pores borne in lateral exca- 
vations of the thickened margins, except on posterior segments where they 
are subdorsal : Genus Taphodesmus, type T. moluccensis (Peters). 
Dorsum with the posterior row of tubercles much more prominent than the 
usuallv inconspicuous anterior rows; lateral margins of carinse not thickened 
nor smooth. ..... ......... 
Copulatory legs with the horn3^ transparent and smooth ungual portion of 
the last joint about twice as long as the oval basal hairy part; basal parts of 
the two legs in situ approximate ; distal portions curved mesad at base and 
crossing each other, after v/hich a broad, short, flat incurved lamina is given 
off the dorsal (anterior) side, v^hile the long slender ramus is again bent mesad 
and recurved upon its fellow, so that a large oval space appears to be entirely 
enclosed between the terminal rami of the two legs when viewed in situ from 
below: Genus Ilodes 7 nus , type /. (Brandt), Manila. 
Copulatory legs with the ungual rami not longer than the hairy basal por- 
tion, and not crossing each other before branching; also not recurved 
Brandtia, p. I. 
