A MONOGRAPH OF THE EXISTING CRINOIDS 



351 



median dorsal spines. The opposing spine does not reach in height one-third the 

 width of the penultimate segment; it arises from the entire dorsal surface of the pen- 

 ultimate segment, and its blunt apex is median or subterminal in position. The 

 terminal claw is longer than the penultimate segment and is stout and slightly curved. 



The IBr series and lower brachials are deep, in close lateral apposition, and later- 

 ally flattened against their neighbors. The synarthrial tubercles are prominent, but 

 small. 



The 10 arms are about 115 mm. hi length. 



P, is 10 mm. long, slender, and flagellate, with 18 segments. P 2 is 15 mm. long, 

 much stouter than P,, with 21 segments, of which the first two are not quite so long 

 as broad, the third is about as long as broad, and the remainder are half again as long 

 as broad. P 3 is 11 mm. long, resembling P 2 though slightly more slender. P 4 is 

 9 mm. long, slightly slenderer than P 3 . P 6 and the following pinnules are 9 mm. 

 long, very slender, and flagellate distally. The distal pinnules are 12 mm. long. 



Notes. Chadwick said that a small specimen was obtained at Ceylon Pearl 

 Oyster Fisheries station I, and two fully grown ones at station LVII. 



The two specimens from Y6, Burma, are typical, and resemble the type specimen 

 in the Copenhagen Museum collected in the "East Indies." The arms are 100 mm. 

 long. The synarthrial tubercles are small, but very prominent. 



Carpenter said that a dozen examples of this species were obtained at King Island 

 in the Mergui Archipelago, half of them from mud flats exposed at spring tide. They 

 were mostly of a light reddish-brown color, but one was more yellowish brown, and 

 another was almost white. Most of the larger specimens have the bases of the rays 

 somewhat flattened laterally, and there is a good deal of variation in the relative sizes 

 of the lower pinnules. P 4 is sometimes considerably shorter than P 3 and sometimes 

 nearly equal to it. 



Hartlaub said that the two specimens from Atjeh that he examined at the Leyden 

 Museum differed in their centrodorsals and in their cirri. In one the centrodorsal is 

 hemispherical, but in the other it is much more flattened and broader. The first has 

 the cirri XV, with up to 33 segments, while in the other the cirri are XXV, with about 

 50 segments. The strong synarthrial tubercles on the articulation between the first 

 two brachials are very characteristic, although they are somewhat variable in their 

 development. The form of the brachials seems also to vary, the brachials in one speci- 

 men being markedly shorter than they are in the other. Both are light grayish brown 

 in color. Hartlaub remarked later (1912) that the wallsidedness of the axillaries and 

 first brachials is very marked in the small specimen from Atjeh. 



In the specimen from Atjeh that I examined at the Leyden Museum (which was 

 the first of the two mentioned by Hartlaub) the cirri are XXII, 32-34 (usually the 

 latter) ; the cirrus segments bear sharp dorsal spines from the tenth or eleventh onward. 

 The synarthrial tubercles are developed as in the type specimen of Amphimetra 

 pinniformis. The size is slightly less than that of the type specimen at Copenhagen. 



The specimen from the Malacca Strait is rather small. 



The specimen from 80 miles northwest of Penang has the arms about 145 mm. 

 long. The cirrus segments are somewhat longer than usual. 



In the example from Singapore in 13 meters the cirrus segments are also slightly 

 longer than usual. 



