Q4 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 113 
posterior ones to segment 15 a little produced caudally (fig. 27), 
thereafter slightly more so; segment 19 with keels reduced in size, 
posterior corners small; dorsum of segments with a broad, faint 
median depression in front of which are two erect setae; median sur- 
face of segments smooth or coriaceous, the keels finely and densely 
granular, margins of keels with raised rims; pores opening laterally 
from the usual segments; outer margin of poreless segments slightly 
longer than the adjacent poriferous ones. Last segment with two 
dorsal setae near apical third; four others at base of apex, two being 
dorsal plus one each side; apex with four long setae; posterior margin 
adjacent to each valve with three setae; preanal scale large, triangular, 
with two long setae. 
Gonopods as in figure 3a-—b. 
Anterior male legs unmodified, like those of female. 
Teinorhachis, new genus 
Tyrer species: Teinorhachis tenuis, new species, by present designa- 
tion and monotypy. 
Draanosts: Related to Strongylodesmus Saussure but much smaller, 
with normal pore formula, and none of the posterior angles of the keels 
are spiniform. Differing from other genera of the family in the shape 
and proportions of body, different widths of poriferous and poreless 
segments on anterior half of body, and the size and shape of the 
gonopods. 
Description: Body slender, loose jointed, gradually narrowed from 
in front. Males less convex than females and with wider lateral 
carinae. Antennae rather slender, joints 2 to 6 about subequal in 
length and thickness; joints 5 and 6 with a small sensory area at 
dorsal apex. 
Segment 1 sublunate, about three times as broad as long. Segment 
2 or 3 widest, narrowing thereafter. Dorsal surface of segments 
smooth, a broad transverse median depression present in front of which 
are two erect setae; lateral keels little projecting in female and lower 
on sides of body, those of male nearly at level of dorsum, the poriferous 
ones on front half of body wider than the adjacent poreless ones and 
with both angles and outer margin more rounded; on caudal segments 
posterior corners are lightly produced; pores opening outward from 
usual segments. Last segment with narrowed apical half convexly 
raised above anterior half; anal valves strongly inflated, margins thin 
and strongly elevated; preanal scale triangular, swollen each side at 
base. Legs long, the four outer joints projecting beyond the keels. 
Gonopods short and stout, subcolumnar, ending in an inwardly 
curved outer plate and two digital processes of different lengths. 
Anterior male legs with secondary modifications. 
