146 
distinct keel in the middorsal line and usually a small spine in 
the centre of the distal dorsal border; 10 — 12 arms; IIBr series, -_ 
if present, 2 (Queensland and Timor to the Philip- 
pine Islands; southern Japan) Daidalometra 
e- arms not narrow nor strongly compressed laterally, and with 
no carination ; sides and proximal and distal edges of the 
ossicles of the division series nearly or quite smooth 
f division series and arms broad, well rounded dorsally; habitus 
robust (Kermadec Islands to the Moluccas and 
t h e P h i 1 i p p i n e s) Aglaometra 
f- division series and arm bases narrower, subcarinate ; general 
habitus slender (Laccadive Islands to the Lesser 
Sun da Islands, Fiji, the Kermadec Islands and 
NewSouthWales) Stiremetra 
d- cirri short and stout, with less than 30 segments; division series 
and arm bases narrow, well rounded dorsally, appearing narrow 
and only slightly flattened against their neighbours; 10 — 20 arms; 
division series all 2 (Kei Islands to southern Japan and 
the Hawaiian Islands) , Parametra 
a- More than 10 arms 
b^ dorsal surface of the ossicles of the division series and of the arm bases 
with numerous prominent spines which may be more or less confined 
to the borders of the ossicles and to the median line, or generally 
distributed over the dorsal surface 
c' more than 15 arms; division series strongly rounded dorsally, appearing 
relatively narrow 
d^ IIBr series all, or mostly, 4 (3 + 4); 15 — 28 arms; a more or 
less prominent median keel on one or both of the elements of 
each division series and of the first brachial pair; no overlapping 
spines on the brachials the distal borders of which are evenly 
rounded and very spinous (Moluccas to the Philippine 
a n d H a w a i i a n I s 1 a n d s) Oceanometra 
d" all the division series 2 ; 30 arms, a single IIIBr series being 
developed on the inner side of each IIBr series; no trace of a 
median keel on the elements of the division series or of the first 
brachial pair; each brachial beyond the fifth or sixth bears a long, 
broad, thin, sharp pointed curved spine of which the base entirely 
spans the ossicle longitudinally and the tip, directed nearly parallel 
to the axis of the arm, extends for some distance over the suc- 
ceeding brachial; on succeeding brachials these spines alternate 
on either side of the median line ; toward the end of the arm they 
