A MONOGRAPH OF THE EXISTING CRINOIDS 431 



segment is about twice as long as the median width, and the longer proximal segments 

 are somewhat constricted centrally, or "dice-box shaped." The IIIBr series are 

 externally developed. The lateral tubercles on the rays are well developed and thick. 

 P 2 is the largest pinnule and is composed of 16 or 17 segments. P 3 is similar but is 

 not quite so long. P 4 is much shorter than P 3 , but stiff, with 11 or 12 segments. P s 

 is slightly shorter than P 4 and resembles the succeeding pinnules instead of being stiff 

 like those preceding, though it may be a trifle stiffer than its successors. 



The specimen from Cocos Island has 30 arms. 



A magnificent specimen from Singapore has exactly 20 arms 95 mm. long and the 

 cirri XXV, 24, 20 mm. long. P 2 is 11 mm. long with 18 segments, stiff and spinelike; 

 the terminal 4-6 segments are abruptly less in diameter than those immediately 

 precjding, giving the pinnule tip the appearance of having been broken off and subse- 

 quently repaired as described by Carpenter in Antedon marginata, and also noticed 

 by Chadwick in a specimen from Ceylon. P 3 resembles P 2 , but is only 8 mm. long 

 and is proportionately less stout. The following pinnules are small and weak. 



A very fine specimen from Singapore has 31 arms about 150 mm. long. The cirri 

 are XXVII, 26, 28 mm. long. The dorsal pole of the centrodorsal is 3.5 mm. in diam- 

 eter and is slightly concave. P 2 is 12 mm. long and is composed of 11 segments. 



A third specimen from Singapore has the centrodorsal small and discoidal with 

 the dorsal pole slightly concave, 2.5 mm. in diameter. The cirri are XXVIII, 20-23, 

 from 15 to 20 mm. long, and slender. The first segment is short, and those following 

 gradually increase in length to the sixth, which, with the three or four following, is 

 twice as long as broad. The succeeding segments gradually decrease in length so 

 that those in the outer third of the cirri are about as long as broad. The shorter 

 distal segments are faintly carinate dorsally. The opposing spine is prominent, and 

 is subterminal in position. P, is 11 to 14 mm. long, with 22-27 segments, equal in 

 length to P a and stiff, but much more slender. P a has 12-13 segments, of which the 

 distal are about three times as long as broad. P 3 is stiff like P 2 , but smaller, 6 to 8 

 mm. long, with 12 segments. P 4 and the following pinnules are small and weak. 



Another specimen with 31 arms resembles the preceding. P 2 is 14 mm. long and 

 is composed of 14 segments. 



A fifth specimen from Singapore has 30 arms 100 mm. long. The cirri are XXX, 

 21-23, from 17 to 20 mm. long. The dorsal pole of the centrodorsal is slightly con- 

 cave, 2.5 mm. in diameter. 



A smaller specimen from Singapore has 14 arms 85 nun. long. On one of the 

 arms arising from a IBr axillary P 3 is exactly like P 2 , though usually it is more nearly 

 like P 4 . In arms arising from IIBr axillaries the relationships of the lower pinnules 

 are the same as in fully grown individuals. 



The specimen from Pulau Obin, Singapore, has 30 arms. 



The specimen from Blakang Mati is a fine example of the species. It has 28 

 arms 125 mm. long. P 2 is 19 mm. long, with 17 segments, and P 3 is 14 mm. long, with 

 15 segments. 



Carpenter said that a single individual that he considered as representing spicata 

 was taken at King Island in the Mergui Archipelago. But it has rather more cirri 

 than the type specimen at Leyden and in this respect approaches the allied species 

 indica ( = protet.tus) and tuberculata, which resemble it in having long and stiff pinnules 



