388 
Mr. W. K. Fisher on 
6’. Superambulacral plates absent, no con- 
spicuous buttress extending from the 
upper enlarged end of the first two pairs 
of ambulacral plates to the body-wall at 
the interradial angle. 
ce’. All adambulacral plates carinate on the 
furrow face. Genotype, Prognaster 
OTUNAAT, POUTIE 15 sarap yeretein se niae 
ce, Adambulacral plates alternately cari- 
nate and non-carinate. 
d', Rays long, slender; disk small; 
abactinal, marginal, and actinolateral 
plates arranged in regular longi- 
tudinal lines along ray, a series of 
adradial plates being always present; 
all but the median radial or carinal, 
which are larger, form also trans- 
verse series ; plates are covered with 
small, papilliform, skin - covered 
spinelets, and most of them bear 
an enlarged spine; papular areas 
generally very small but sometimes 
nearly as large as plates; fortici- 
form pedicellariz present ; actino- 
lateral plates in three to five series, 
the upper subequal to the infero- 
marginal plates; superomarginal 
plates not conspicuously larger than 
the inferomarginal plates. Geno- 
type, Zoroaster fulgens, Thomson .. 
d*, Plates of ray arranged in regular 
. to} fo] 
longitudinal series, the  carinal 
plates the largest; abactinal and 
marginal plates armed with fairly 
large, skin-covered scales which 
mask all plates except some of the 
disk-plates and the carinal series 
along ray; no pedicellariz ; actino- 
lateral plates, in two or three series, 
much smaller than inferomarginals ; 
superomarginal plates much larger 
than inferomarginal plates. Geno- 
type, Pholidaster squamatus, Sladen. 
&?, Superambulacral plates present; a con- 
spicuous buttress, the specialized first 
superambulacral plate connects the 
upper end of the first two ambulaeral 
plates with the body-wall at interradial 
angle. 
Prognaster *, Perrier. 
Zoroaster, Thomson, 
Pholidaster, Sladen. 
* Prognaster, Perrier, ‘Comptes rendus,’ exil. no. 21, May 5, 1891, 
Type, P. grimaldu. Also ‘ Résultats des campagnes scienti- 
tiques du Prince de Monaco,’ fase. xi. 1896, p. 22, pl. il. tigs. 1, la—-b. In 
the meantime, Perrier described Prognaster as a new genus with P. longz- 
cauda, new species, ostensibly as type (xpéd. scientif. du ‘ Travailleur’ et 
p. 1226. 
du ‘ Talisman,’ 1894, p. 119). 
This species does not seem to be con- 
generic with grimaldi, which, of course, is the genuine genotype. 
