ASTEROIDEA OF NORTH PACIFIC AND ADJACENT WATERS — FISHER 3 



and sunken in actinostome but primitively strong and spiny, as in the Brisingidae, 

 Labidiasterinae, and most Pedicellasterinae. Papulae few to many, frequently in 

 clusters, usually on all surfaces, in adult. Spines vary in form from coarse granules 

 to long delicate needles. 



SYNOPSIS OF THE KNOWN SUBORDERS AND FAMILIES OF FORCIPULATA 



a 1 . Ambulacral ossicles not compressed; upper end of ossicle sub-cylindrical or hour-glass-shaped, 

 the pair closely joined by a muscular symphysis; consecutive pairs articulated end to end 

 without overlapping and resembling centra of a vertebral column; ambulacral pores large, 

 biserial; adambulacral ossicles stout, cylindrical, or hour-glass-shaped; odontophore super- 

 ficially visible on margin of small circular disk, as an "interradial" plate; papula? often 



lacking Suborder Brisinoina Fisher, new. 



Deep-water Forcipulata with characteristic small circular disk, slender, often deciduous 

 rays, sharply differentiated from disk, and long, delicate, sacculate, acicular marginal 

 and adambulacral spines; dorsal skeleton weak, that of ray variable, never reticulate, 

 confined to proximal third or half of ray, composed of transverse, independent parallel 

 ridges or costae, separated by areas of integument without plates; or the intervals may 

 be partly or completely filled with more or less perfectly developed plates immersed in 

 the body wall; or the arches may be absent and a tessellation of these plates may cover 

 the genital region of ray; or there may be thin plates, more or less spiniferous, together 

 with differentiated transverse costae; straight pedicellariae absent; crossed, abundant; 

 gonads two to many attached to lateral integument of basal portion of ray; actino- 

 stome relatively large, peristome broad; mouth plates expanded, usually with promi- 

 nent spines Brisingidae Sars. 



a 1 . Ambulacral ossicles compressed, the upper ends short, often imbricated (not subcylindrical and 

 centriform); adambulacral plates short, compressed; odontophore entirely hidden, 

 never exposed on margin of disk; papulae never lacking in adult; marginal plates 

 normally well developed; abactinal skeleton normally of lobed plates imbricated in 

 series or linked by intermediate plates into a regular or irregular reticulum. 



Suborder Asteriadina Fisher, new. 



b l . Only straight pedicellariae present; deep-water species with very small disk and normally 



five, slender, usually subterete rays, the plates of which are arranged in regular, usually 



closely juxtaposed, longiseries; alternate adambulacral plates (in one genus, all) with a 



prominent spiniferous projection into furrow Zoroasleridae Sladen. 



6'. Straight and crossed pedicellariae; abactinal skeleton normally a regular or irregular reticulum; 

 adambulacral plates without a prominent spiniferous projection into furrow; rays five 

 to many and disk variable; shore to moderate depths. 

 c 1 . Ccelom of disk separated from that of ray (except for a small dorsal passage) by a contin- 

 uous oblique or horizontal shelf or discobrachial wall, 3 which extends from the acti- 

 nostomial ring to the dorsal surface of disk, fusing with the inner edges of the inter- 

 radial septa which it covers; the inner edge of the shelf passes over the upper end of 

 the second pair of ambulacral ossicles and just external to outer border of odontophore 

 so that the ambulacral ridge (distad to the first plate) can not be seen from ccelom of 

 disk; ventrally, ccelorn of ray ends in a shallow cul-de-sac near inner end of ambulacral 

 ridge where in Asteriidae the ccelom of disk communicates with that of ray. Rays 

 numerous, disk large; bases of rays fused for a variable, but considerable, distance, the 

 juxtaposed sides forming the so-called double interradial septum; skeleton reticulate, 

 robust. West Coast of Mexico, Central, and south America Heliasieridae Viguier. 



1 First described by Clark, The Starfishes of the Genus Heliaster, Bull. Mus. Comp. Zool., vol. 51, No. 2, 1907, p. 67, pi. 6, 

 fig. 1. 



