254 ECHINODERMA OF THE InDIAN MuSEUM, PART Vll. 



COMASTROCRINUS SPRINGERI. 



Hypalocrirms sprhigcri 1909. A. H. Clark, Proc. U.S. Nat. Mus.. vol.36, 

 p. 650. 



Description. ^Stem slender, 4 mm. in diameter, rounded pentagonal in 

 cross section, the sides smooth, flat, or very slightlj' convex: interarticular 

 pores extending to the eighth node : internodals 10 (rarely 9 or 11), of equal size, 

 each face slightly over twice as broad as high ; nodals slightly longer than the 

 internodals, the small transversely oval cirrus sockets touching the distal (lower) 

 border and extending upward to the proximal fourth of the joint face ; neither 

 the supra- nor the infranodals are modified in any way. 



Cirri slender and delicate, twelve times the diameter of the stem in length 

 (48 mm.), with fifty segments ; first segment very short, the following gradually 

 increasing in length to the fourth, which is twice as broad as long, and still 

 further increasing to the sixth, which is about as long as broad; following seg- 

 ments slightly long<^r than broad, but in the terminal fourth becoming again 

 about as long as broad ; from the twentieth to the twenty-third segment onward 

 small but pr'ominent median dorsal tubercles are developed ; terminal claw small 

 and blunt, conical, twice as long as broad at the base, slightly longer than the 

 preceding segment. 



Infrabasals present, resembling those of Isocriniis dccurus ; basals promi- 

 nent externally, rhombic in outline, just contiguous by their lateral angles, 

 strongly convex exteriorly, bearing from one to three prominent tubercles ; in 

 dorsal view the basals form a figure similar to that made by the basals of Isocri- 

 nus decoriis; radials large, strongly convex proximally, slightly concave distally, 

 about half again as broad as long, ornamented with a few coarse high tubercles, 

 irregularly placed; IBr, oblong, about twice as broad as long, without orna- 

 mentation; the lateral edges are ]ust in apposition but are not flattened; they 

 are cut away somewhat anteriorly and posteriorly, forming small rhombic pores 

 on the lines of articulation between the IBr, and the radials, and between the 

 IBr, and IBr^ ; IBr^ short and broad, triangular, two and one half times as broad 

 as long, the anterior edges everted and produced into a high scalloped ridge; 

 IBr, and IBr, united apparently by syzygy; IIBr 2, the distal edges of the seg- 

 ments standing out in high prominent scalloped ridges; IIIBr 4 (:i-|-4), the 

 distal edges of the IIIBr,, ^, and ^ forming high scalloped vertical ridges. 



About twenty-five arms 140 mm. long, the terminal 30 mm. being slender 

 and bearing only very rudimentary pinnules as in the species of Metacrinus and 

 Hypalocrinus; first brachial very obliquely wedge-shaped, the distal edges form- 

 ing a straight line with those of adjacent first brachials and standing out in a 

 high scalloped vertical ridge or bearing two or three high tubercles, the interior 

 edges entirely united; second brachial smaller, wedge-shaped, about twice as 

 long outwardly as inwardly, the distal edge everted as in the preceding; following 

 brachials obliquely wedge-shaped, about twice as broad as long, after the twelfth 



