ANNOTATED LIST. 37 
pa Key to the Genera of Ophidiasteride. 
A. Abactinal plates of ray not in regular longitudinal series (except on basal part of ray in Narcissia, 
Certonardoa, and Plenardoa).* 
B. Adambulacral armature spiniform, often subprismatic, in 1 to 3 series, often quite gonias- 
teroid. (In some genera the distinction between spiniform and granu- 
liform armature becomes very obscure.) 
C. Actinal intermediate area rather large, many of the plates with conspicuous stout spines; 
primary plates of disk also with stout spines...............0000ee ees Dissogenes 
CO. No conspicuous spines on abactinal plates or on small actinal intermediate areas. 
D. Papulz on actinal surface as well as on abactinal. 
E. Papule isolated. 
F. Size moderate or small, usually much less than 100 mm. across alternate rays; 
seldom more than two series of actinal papule....................... Fromia 
FF. Size large, 100 mm. or more across alternate rays; 3 to 6 series of actinal papule Austrofromia 
EE. Papule in groups; adambulacral armature in 3 (rarely 2) series; rays more or 
TESSMLETELEI en mace el eae he nae. conve Sects slomeeecie Bae aia ae See eee ee 
DD. No papulz on actinal surface. (Very rarely single isolated papule occur just between 
lower corners of inferomarginals.) 
BK. Many abactinal plates swollen to form conical tubercles with naked acute tips... Gomophia 
EE. No abactinal plates conical with naked acute tips. 
F. Adambulacral armature more or less goniasteroid in 2 or 3 series; rays more 
or less trigonal at base. 
G. Papul in groups; abactinal plates at base of ray in longitudinal series.. Cerlonardoa 
GG. Papulz isolated. 
Many (16 or 18) series of plates on abactinal surface of ray......... ... Plenardoa 
Few (7 to 13) and irregular series of plates on abactinal surface of ray... Narcissia 
FF. Adambulacral armature in a single series..............-.00-eeeec ee ceeees Ferdina 
BB. Adambulacral armature granuliform, in 2 or 3 series (rather spiniform in Phataria); disk 
small; rays not flattened. 
C. Papule in groups, rarely on actinal surface; skeletal plates covered with granules. 
D. Papular groups irregularly scattered among abactinal ossicles; rays more or less 
Nardoa 
CyLINGTICALOS - Psi ete seis Date re oleae EE Cee elke SaaS aeRO Linckia 
DD. Papulz in one or two continuous series of groups on each side of trigonal rays..... Phataria 
CC. Papule on both actinal and abactinal surfaces, usually single, but sometimes in groups 
of 2 to 4; skeletal plates swollen, bare, separated by granules.......... Bunaster 
AA. Abactinal plates in regular longitudinal series. (Not clearly shown in some Ophidiasters.) 
B. Body-wall rigid with well-developed abactinal skeleton; never more than 10 series of papular 
areas on a ray. 
C. Rays cylindrical, nearly smooth, formed of rows of 3-lobed flat ossicula, each furnished 
with a central mobile spine (Gray).........+....5. Sa Neyereteteuseleee ... Cistina 
CC. No central mobile spines on abactinal surface of rays. 
D. Whole test covered with a thick, smooth, membranous skin..............-00--05 Leiaster 
DD. Whole test granulose; i.e., underlying a membrane more or less covered with granules 
or little tubercles. 
E. Madreporic body large, becoming compound in adults (even in young, it is one- 
fifth of disk diameter); papular areas becoming confluent laterally in adults Pharia 
EE. Madreporic body simple, its diameter less than one-fifth of disk diameter. 
F. Papular areas present on actinal surface, at least one series below infero- 
marginals. 
G. Papular areas in 8 series, only one below inferomarginals on each side; ? 
rays cylindrical. 
H. Skin uniformly granulose, though granules are commonly largest on 
CONVEXILIEN Of SKCIE TOME s farccloves-/oiaie ems at chose lo shorts. -lkeieniye eeltey: +. 
HH. Skin naked and thin except on convexities of skeleton, each of which 
carries a cluster of unequal, coarse, squamiform or spinuliform grains 
Ophidiaster 
OT PUErclese sate an es rasa eae oe eco ciate Ga eta teeters wt oaieare sta cere Dactylosaster 
GG. Papular areas in 10 series, one nearest adambulacrals made up of twice 
as many areas as others but often more or less incomplete ; rays often 
BoMe whationponalat DAREN ese. mass olleeiescieielett eieieicite/</niniels ciate/eialaieiel ear Hacelia 
FF. Papular areas in 6 series, wanting on actinal surface or below inferomarginals; 
though isolated papule and rarely scattered groups of 2 or 3 are some- i 
‘amaria 
TEMES! PreESeMtUNEKe aerators ope iaiaie. = =cssisielepepetedere leloie/e sist min) ois) =\n's).sleieisi Soo 
BB. Body-wall thick and leathery without a rigid abactinal skeleton; in adults, 12 series of 
papular areas may be found at base of high trigonal rays............. Pseudophidiaster 
1 In some Ophidiasters the serial arrangement may be obscured, particularly in old age, and such specimens may 
be vainly placed in this section of the key, but the general facies is usually sufficient to make an Ophidiaster recognizable. 
4Tsolated papule may occur between actinolateral plates, but this is very unusual. 
