A MONOGRAPH OF THE EXISTING CRINOIDS 547 



segments, resembling P 3 , while on arms arising from a IIBr axillary it is 9 mm. long, 

 with 20 segments. P 6 is much shorter than P 4 , and the pinnules following are small 

 and weak, of approximately uniform size. From about the fifteenth or sixteenth pair 

 the length slowly increases so that the distal pinnules are 7-9 mm. long. The enlarged 

 lower pinnules are more or less stiffened and wiry. 



The disk is 15-25 mm. in diameter and is incised. Sacculi are numerous to very 

 abundant along the pinnule ambulacra. 



Notes. The specimen from 8 miles outside Hongkong Harbor agrees well with 

 the specimens from Singapore, with which it was compared directly. It has 35 arms 

 115 mm. long. The IIIBr series are all externally developed. The cirri are XXII, 

 26-29, from 15 to 20 mm. long. 



The two specimens from east of Hongkong are both small, with 28 arms 65 mm. 

 long. In one the cirri are XXVI, 25-27, 15 mm. long. 



The specimen from Hongkong has 45 arms about 80 mm. long; the cirri are XXII, 

 34-39, up to 25 mm. long. 



The specimen from the North China Sea was identified by Hartlaub as Antedon 

 elongata. He said that in 1891 he had compared a specimen of this relatively rare 

 species (elongala) from Amboina directly with the type specimen from New Guinea 

 in the Leyden Museum and had found various differences. It is therefore of interest 

 to see how the specimen from the North China Sea stands in regard to these differ- 

 ences. The centrodorsal, which in the Amboina specimen is rather large, quite flat, 

 and encircled by marginal cirri arranged approximately in a single row, and in the 

 type specimen is "moderately thick convex" and bears two rows of cirri, in the specimen 

 from the China Sea is markedly smaller, discoidal, and encircled by more numerous 

 cirri that are arranged in at least two rows. The cirrus segments, of which in the speci- 

 men from Amboina the 10 or 11 outermost bear no dorsal spines, in the Chinese speci- 

 men are from the tenth onward armed with small spines, so that the latter agrees 

 better with the type specimen from New Guinea. The position of the second syzygy, 

 which Carpenter gives as usually from between brachials 9 + 10 to between brachials 

 18+19, though in the Amboina specimen it is not proximal to brachials 15 + 16, 

 appears in the Chinese specimen as a rule to occur as in the latter. On one arm Hart- 

 laub found the second syzygy between brachials 9 + 10; but it was not possible to make 

 an accurate determination of the position of the syzygies because the arms were 

 recurved dorsally. The lower pinnules of the Chinese specimen are very much broken; 

 nevertheless on an outer arm it is seen that P 3 is markedly longer than P 2 and also 

 longer than P 4 . P 3 is 11 mm. long and is composed of 28 segments, of which those 

 from the eighth onward are markedly elongated. In its distal portion the pinnule 

 becomes very slender and flagellate. Of quite similar character is P 2 , which is 8 mm. 

 long; but it tapers earlier and more abruptly from the fifth segment onward. Hart- 

 laub was not able to measure P 4 on the same arm. But on another outer arm P 4 was 

 9 mm. long, with 22 segments. One P a that Hartlaub was able to measure was 6 mm, 

 long with 21 segments. The pinnules of the first pair are markedly weaker than those 

 following. The uneven and rugose surface of the basal portion of the arms to which 

 Hartlaub in 1891 called attention as especially characteristic of the two specimens 

 known at that time is likewise typically developed in the Chinese specimen. It appears 

 therefore to be one of the best diagnostic characters of the species. 



