A MONOGRAPH OF THE EXISTING CRINOIDS 329 



syzygial pair (composed of brachials 3 + 4) is roughly oblong, with a somewhat raised 

 forward projection from the inner part of its distal edge. The fifth brachial has a 

 corresponding elevation at the inner side of its proximal edge so as to give a some- 

 what tubercular appearance to the line of junction. The same feature is visible on 

 the outer part of the line of junction between the nearly oblong fifth and sixth bra- 

 chials, and recurs alternately on opposite sides of the arm for a few brachials further. 

 As the brachials become flatter and more triangular, with curved edges, it gradually 

 disappears. These brachials are rather more than half as long as broad, with a very 

 faint slightly raised median line, and retain the triangular shape and the curved edges 

 as far as the one hundred and sixtieth, narrowing and becoming blunter at the extreme 

 ends of the arms. 



Syzygies occur between brachials 1+2, 3 + 4, and 11+12, then at intervals of 

 from 4 to 7, usually 5 or 6, muscular articulations. The hypozygals of syzygial pairs 

 are very short. 



PI and P a are long, about 25 mm. in length, and moderately stout. They 

 consist of about 60 segments, of which the first 3 or 4 are nearly square and those 

 following are shorter and more oblong and gradually decrease in width, the outer 

 edges of the last 30 bearing the strong lancet-shaped processes forming the terminal 

 comb. P a and P 6 are smaller with fewer segments, only the first 2 of which are 

 about square, while they have no dorsal keels. They also have a well-marked 

 terminal comb, but this appears to be wanting on P 3 and P c , which are still smaller, 

 with short and wide triangular basal segments. P 4 and P t are as long as, or longer 

 than, P 3 and P c but stouter, with broader and more massive segments. The following 

 pinnules increase in both length and stoutness, and consist of about 30 segments, the 

 first half of which are about twice as broad (2 mm.) as long, with sharpened dorsal 

 edges which are sometimes produced into slight keels. The largest pinnules are 

 those between the tenth and twenty-fifth brachials, and a little further on they 

 become more slender with squarer segments, the terminal pinnules having some- 

 what elongated segments. 



The disk is 25 mm. in diameter, without any trace of calcareous deposits. 



The color of the specimen (dry) is black. 



The preceding description was partly based on a second dry specimen also bearing 

 the manuscript name robusta in the collection of Dr. W. B. Carpenter. 



Carpenter remarked that robusta has a considerable resemblence in general 

 appearance to Solaris, both having large arms composed of massive triangular brachials 

 with curved edges, and stout pinnules composed of broad segments. The arm bases 

 of Solaris, however, are nearly or quite smooth and have little tendency to alternate 

 tubercular elevations, such as are visible in robusta. In the latter, too, the width of 

 the arms increases more distinctly in the first few brachials than in Solaris, while the 

 second and third pairs of pinnules have no expanded keels on the lower segments, 

 such as appear in Solaris, and the cirri are larger and more numerous. 



Carpenter thus described a specimen from Hong Kong in the Hamburg Museum. 

 The centrodorsal is a thin pentagonal disk bearing 2 cirri at each angle. 



