ASTEROIDEA OF XOUTH PACIFIC AND ADJACENT WATERd — FISIIEK. 369 



KKV TO THE KNOWN SPECIES OF PTEHASTKR - <(>IllillU<'il. 



e'. Stalk iif paxilla high and slencier with eix or neveii Mpiiips; nral fipincsi five ur six. 



airi66arui Perrier. 

 (P. Ambulacral comb with three to five spines, 

 e". Oral spine very large and three-edged; paxilla stalk high with six spines; adambulacrol 



spines five Irigonodon Kisher. 



e^. Oral spine not three-edged. 

 p. Oral spines six; supradorsal membrane thick and Hm(x)th with spiny calcareous b>xlie«; 



paxilla stalk low; three to five adambulacral spines Ubruni Perrier. 



p. Oral spines four; supradorsal membrabe thin; paxillse with numeroun (five to ten) 



epiaelets; four adambulacral spines affinit Smith. 



c'. Tube feet intwoseries; supradorsal membrane thin, delicate, reticulated, and without deiKjsiu; 



oral spines two, independently webbed grarilU < lark. 



c'. Tube feet in four series, at least proximally; supradorsal membrane either without deposits or 

 wiih a yen,- few simple rods. 

 (/'. Adambulacral comb of three or four spines; oral spines four; no small lateral pockets back of 



aperture papilla; no deposits in supradorsal membrane; spiracula _;orrfan i Fisher. 



(P. Adambulacral comb of five spines proximally; oral spines five; small shallow [xxkets just 

 back of aperture papillae; supradorsal membrane with a few scattered simple rods; 



spiracula absent manippua Fisher. 



6-. No suboral spine present. 



c'. Adambulacral spines five, in curved serie.-*; oral spines five pn-jona/u.) Sladen. 



I?. Adambulacral spines four, in straight series; oral spines six aordidua Perrier. 



(?. Adambulacral spines six or five, oral spines six; fifteen to twenty spinelets to paxilla, 



compact redudus" Kcehler. 



a-. Rays very short; R less than 1.8 r, usually 1.3 to 1.7 r; form often mot« or less pentagonal (that is 

 in pentamerous species); suboral spine present. 

 6'. Rays regularly five, 

 c'. Adambulacral armature five to seven spines. 

 d'. Oral spines united by membrane. 

 «'. Oral spines five to seven, the two series joined by a single continuous membrane; abactinal 

 surface swollen and sometimes more or less warty in adult. 

 p. Membranes thick and fleshy; size large; supradorsal membrane more or less reticulated, 

 or else creased by fine furrows into which open the spiracula; R = 1.4 to 1.8 r. 

 3'. With well-developed rays; R = 1.6 to 1.8 r; with reticulated mernhnne... Ies»elatiu Ives. 



g'. Arcuately pentagonal inform; R = 1.44r. No evident reticulations arntatus Fisher. 



p. Membranes not especially thick, but rather thin, often translucent; R = 1.3 r. 



g'. Paxillse with high pedicel and five to fifteen spines; suboral spine slender cylindrical; 

 mu.scle bands connecting tips of paxillar spines; aperture slits small; oral spines 

 .six to seven; no deposits in supradorsal membrane; lateral fringe not defining 



ambitus pulfilliu Sarsi. 



^. Paxilloe low, with low pedicel and five to seven short spines; suboral spine with three 

 sharp edges; no muscle bands connecting tips of paxillar spines'; aperture slits 

 unusually large; oral spines five; in supradorsal membrane, depo«t» in the form of 



branched rods; lateral fringe defining ambitus temnochilim Fisher. 



e'. Oral spines three, the series independently webbed; abactinal surface not much elevated 



and not at all warty; adambulacral spines, six muUitpintu Clark. 



(f. Oral spines free, not webbe<i. 



«'. Actinolateral membrane defining ambitus; first two (innermost) oral spines not (lattened 



and truncate; actinolateral spines much longer at middle of ray than near tip. 



p. R = 1.7 r; suboral spine very heavy club-shaped, with an incipient threo-sidwl p«>int; 



supradorsal membrane with reticulations, oral spines five to seven; spiracin* not 



exceedingly numerous reticulalxu Fisher. 



u Very close to pertonatua: according to Kcebler, distinguished by its constantly smaller size, romp«cl 

 paxilla?, longer adambulacral and oral spines, with one more spine in each series. 



574-14°— Bull. 70—11 24 



