STAEFISHES OF THE PHILIPPINE SEAS. 211 



row spines. It differs from B. spiyiosus V'errill in having pedicel- 

 lariae, in having only 2 (and larger) iniercmarginal spines, smaller 

 disk, smaller actinal intermediate areas, and more numerous long, 

 abactinal disk spines, which are graduated in length into those of the 

 ray, not abruptly larger as in spinosus. B. spinosus is of a much 

 stouter habit, as is also B. mutahilis, which does not at all resemble 

 moluccanus, having the abactinal spines abruptly larger in the middle 

 of the disk. B. acanthonotus differs in having a shorter furrow 

 comb with 4 to 5 spines, several prominent accessory inferomarginal 

 spinules and 1 to 6 accessory spinelets in connection with the abac- 

 tinal spines of disk, and in having the inferomarginal pedicellariae 

 confined to base of ra3^ 



BENTHOPECTEN POLYCTENIUS Fisher. 



Plate 51, figs. 2, 3 ; plate 52, fig. 2 ; plate 55, fig. 4. 

 Benthopecten polyctenius Fisher, 1913c, p. 208. 



Diagnosis. — Closely related to B. violaceus (Alcock), but differing 

 in having abactinal pedicellariae, inferomarginal pedicellariae far 

 along the ray (in adult specimens), more numerous furrow spines, 

 and 20 instead of 24 adambulacral plates to the first 10 inferomargi- 

 nals. R=224 mm., r=18 mm., R=12-|-r; breadth of ray at base, 

 23 mm. Abactinal area of large specimen with numerous large 

 pedicellariae extending far along ray; abactinal plates with 4 to 8 

 short spinelets, and scattered spines on disk only; superomarginals 

 with 1 spine, together with 2 unequal accessory spinules and 3 or 4 

 slender spinelets proximally, and only 1 accessory spinule over most 

 of ray ; 2 inferomarginal spines ; 2 subambulacral spines, with often 

 a third, smaller accessory; furrow spines 13 or 14 (9 or 10 on first 2 

 plates) ; 7 or 8 oral spines and 3 to 5 suboral spines; 20 adambulacral 

 plates correspond to the first 10 inferomarginals. omitting the odd 

 plate. 



Description of type. — Abactinal area with only short spinelets on 

 rays and a few scattered spines on disk, the largest on the primary 

 basal plates. Plates of ray with commonly 5 to S very short spine- 

 lets, which become abruptly longer and thicker on the papular area 

 of disk and base of ray, where there are usually 4 to 6 to a plate. 

 The spinelets are round tipped, slightly roughened, and invested 

 with membrane. The spines of the disk are surrounded by upward 

 of 10 spinelets. Numerous large pedicellariae composed of 2 or 3 

 combs of about 5 to 7, slightly curved, pointed or blunt spines are 

 scattered over disk and for a variable distance along the median 

 line of ray — usually nearly to the end. The pedicellariae on the disk 

 are 1.75 to 2.25 mm. in diameter. 



Papulae distributed all over disk and on the ray as far as the 

 fourth superomarginal, the distal margin of the area being tv»'o- 

 lobed. 



