194 THE VOYAGE OF H.M.S.. CHALLENGER. 
The general distribution of all the recognised species of which the locality is known is, 
given under the section on the chorology of the genus. 
A number of forms which are structurally different have been at various times referred 
to the genus Astropecten, but it is unnecessary to recapitulate here the list of the erroneous 
references corrected by previous workers. The grounds for the removal of those forms 
with which the present Report is concerned will be found discussed in their proper 
place. 
The following scheme will assist in showing the relative characters of the species 
obtained by the Challenger Expedition. 
Synopsis of the Species included in the Genus Astropecten herein described. 
A. With two series of definite spines on the supero-marginal plates. 
a. Three lateral spines. Adambulacral armature with three spines in the furrow 
series, and three also in the second series, the aboral largest . : B brasiliensis. 
b. One lateral spine. Adambulacral armature with four or five spines in the 
furrow series; the actinal surface of the plate occupied by a group of 
papilliform and equal-sized spinelets . : : ° : . brevispinus. 
B. With one series of definite spines on the supero-marginal Pintes 
a. With large, prominent spines on the supero-marginal plates. 
a. With large, well-developed spines on the infero-marginal plates. No 
naked spaces : 5 < : . ¢ . polyacanthus. 
b. With small spines on the supero- saan rlaten 
a, The series of supero-marginal spines continuous throughout the ray. 
«. Lateral spines four, in an oblique comb. Adambulacral 
armature in three series, with three spines in each pectinatus, 
&. One lateral spine, long and cylindrical, with two small com- 
panions close behind. Adambulacral armature with 
the spines of the second and third series frequently 
grouped, normally three in each. A spine on the 
infero-marginal plate near the adambulacral plates . acanthifer. 
b. The series of supero-marginal spines not continuous throughout the 
ray. 
a. Wanting in the interbrachial are. 
i. One lateral spine. Adambulacral armature in three 
series . 4 5 : 5 . japonicus, 
§. Wanting on the outer half of the ray, but continuous in the 
interbrachial are. 
i. Three lateral spines. Adambulacral armature in two 
series . : : . ° . . ° imbellis. 
C. With only an indefinite spinelet, or several Saige granules, on the supero- 
marginal plates, 
a. One lateral spine. 
a, Adambulacral armature with usually two spines in the second series, 
.very broad and flaring. No aboral line of spinelets on the 
infero-marginal plates. Actinal spinulation chisel-shaped and 
truncate. Lateral spines much flattened : 5 ° hermatophilus. 
