198 
XX — XLV (rarely over XL); arms 23 mm. to 30 mm. long 
(from the Red Sea to Madagascar and Mauritius, 
eastward to northern Australia and the East Indies, 
and northward to s o u t h er n J a pa n ; o — 106 Metres) . Dorometra 
e- larger, with 16 — 33 cirrus segments; cirri more numerous, 
XXXV — LX (rarely less than XL); arms 75 mm. to 80 mm. 
long (Lesser Sunda Islands to the Philippines; 69 — 140 
Metres) Eumetra 
c'- P.. not much the longest and stoutest piimule on the arm 
cP Pj, P„ and Pg similar and of approximately equal length, with at 
least I 3 segments 
e^ Pj , P„ and P.^ longer than the genital pinnules ; the pinnules are 
not especially stiffened, and their component segments do not 
bear prominent spines on the distal edges ; the centrodorsal is 
low hemispherical (Philippine Islands to southern Japan; 
23 — 192 [? 250] Metres) Iridometra 
e" Pj, P., and P., shorter than the genital pinnules; all the pinnules 
slender and stiff, especially the lower which are thorn-like, with 
long spines on the distal edges of the segments ; the centro- 
dorsal is large, rounded conical (coast of Brazil; 41 Metres) Hybometra 
d" P, much longer than P., and longer than P.,, thouoh similar to 
the latter : centrodorsal more or less sharply conical (Andaman 
Islands to southern Japan; 54 — 201 [?25o] Metres) 
Andrometra 
Mastigometra A. H. Clark. 
Key to the Species of the Genus Mastigometra. 
a^ Distal cirrus segments from one thirds to one half again as long as broad; 
arms from 105 mm. to 120 mm. long; cirri XXXV — LXXX, 12 — 16, 12 mm. 
to 14 mm. long 
b' Pj 25 mm. long with 40 segments; P, 16 mm. long with 35 segments; ^ 
P.5 10 mm. to 12 mm. long with 25 segments (locality unknown). . Jiagcllijcra 
b- Pj 15 mm. long with 30 segments; P„ 10 mm. long with 24 segments; 
P^ 7 mm. long with 13 — 15 segments (Ta h i t i ; 1 i 1 1 o r a 1) pacijica 
a- 6"' and following cirrus segments about as long as broad; cirri L — XC, 16, 
about lo mm. long; arms probably about 80 mm. long (Ceylon; o — 47 
Metres) , . . . inicropoda 
I. Mastigometra flagellifera A. H. Clark. 
A. H. Cl.\RK. Proc. Hiol. Soc. Washington, vol. 21, 1908, p. 229 [Mastigometra fiagflUf era). 
