^o. 1685. HEVISIOX OF CRICOID FAMILY COM ASTERID.¥.— CLARK. 505 



lateral edges diverging distally and about equal in length to those 

 of the IBr^ ; IIBr 4 (3+4) ; IIIBr 3 (2+3), the division series being 

 separated by a distance about equal to the breadth of the IIBr series; 

 if the full IIIBr series is not present, those on the exterior sides of 

 the IBr series are most fi'equently absent, so that there is an approxi- 

 mation to a 1, 2, 2, 1 arrangement. 



Twenty-four to thirty-one arms, about 20Q mm. long; first brachial 

 Avedge-shaped, rather large, not quite half again as broad as the 

 exterior length, almost entirely united interiorly; second and third 

 brachials (syzygial pair) not quite so long as broad; next four 

 brachials oblong, about twice as broad as long, then wedge-shaped, 

 and after three or four triangular, about as long as broad; in the 

 terminal portion of the arms the brachials become wedge-shaped, 

 nearly or quite twice as long as broad. The distal edges of the 

 brachials project slightly and are beset w^th fine spines. Syzygies 

 occur between the second and third brachials, again between the 

 fourteenth and fifteenth to twenty-second and twenty-third (usually 

 in the vicinity of the eighteenth) and distally at intervals of three 

 oblique muscular articulations. 



Mouth marginal and radial; anus central; disk naked, about 30 

 nun. in diameter; side plates developed along the brachial and pin- 

 rude ambulacra. 



Pd 30 mm. to 35 mm. long, stout, much stouter than the succeeding 

 pinnules, but tapering evenly to a slender and flagellate tip, Avith 

 forty to forty-five joints, all of which are approximately squarish; 

 a slight prominence is visible on the dorsal side of the distal edge 

 of the second joint, Avhich rapidly becomes larger and increases in 

 width on the succeeding joints, after about the seventh taking the 

 form of a strong coarsely spinous eversion of the dorsal edge of the 

 joints; this disappears near the proximal part of the distal comb; 

 comb composed of fourteen teeth, arising abruptly; first tooth low 

 and triangular; second oblong or slightly trapezoidal, usually 

 slightly broader basally than high, the following becoming more 

 obliquely trapezoidal and relatively somewhat higher, the terminal 

 teeth being truncated-triangular; the more proximal teeth are not 

 equal in height to more than three quarters of the lateral diameter 

 of the joints which bear them, but the later teeth, owing to the dis- 

 tal tapering of the pinnule, become about equal to the lateral diameter ; 

 Pp about 25 mm. long, considerably less stout than Pd, but otherAvise 

 similar to it ; P^ about 20 mm, long, much less stout than Pp, similar 

 to it; P^ and folloAving pinnides slender and delicate, about 10 mm. 

 long; Po bears a comb distally, but the following pinnules are with- 

 out combs; PP2, 3, 4, and „, h-, c have the first two joints dispropor- 

 tionately large and produced dorsally into large carinate processes; 

 distal pinnules slender, about 12 mm. long, with about twenty-five 



