470 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



slender, P 2 being very delicate. P 3 is 8 mm. long with about 27 segments; it is 

 about as stout as P 2 , but the corners of the segments are more broadly cut away, and 

 there is considerably more ventral perisome. The following pinnules are similar, but 

 slightly stouter with a more serrate outline, the short segments with somewhat 

 prominent and finely spinous distal ends. The terminal comb disappears at about 

 P 6 or P 8 , rarely extending to P 20 . The distal pinnules are slender, about 7 mm. 

 long, with about 18 segments, the longest of which are scarcely longer than broad. 

 On postradial series where the IIBr series are 2 and P D is therefore absent, P P is 30 

 mm. long, resembling P D as described, and the following pinnules decrease in size as 

 given above. 



Notes. The specimen from Suvadiva is of enormous size. 



Of the 2 specimens recorded by Dr. H. L. Clark from Ceylon 1 has about 120 arms. 

 In the other, which I have personally examined, there are about 100 arms; all of the 

 IIBr series are 4 (3 + 4); the centrodorsal is on a level with the dorsal surface of the 

 radials. 



The specimen from off Tobu Island is small with about 70 arms many of which 

 are arising by multiplicative regeneration from broken IIBr series, showing that the 

 individual is just passing into the adult stage. The arm division is perfectly regular, 

 all the division series being 4 (3 + 4) except the exterior IIIBr series, which are 2. 

 The dorsal perisome is plated. The centrodorsal is thin discoidal with a few rudi- 

 mentary cirri and a single fully developed cirrus on the periphery; the last is 10 mm. 

 long and consists of 14 segments. 



The specimen from Invisible Bank has about 120 arms which are 130 mm. long. 



One of the examples from Singapore has nearly 100 arms which are 100 mm. 

 in length. There are no cirri, but the centrodorsal is slightly raised above the surface 

 of the radials. The interspaces between the division series and lower pinnules where 

 they are not in apposition are occupied by large irregular plates which, however, are 

 not so evident as in larger and more developed individuals from the Philippines. 



The other specimen from Singapore is young, with 37 very attenuate arms 

 150 mm. long. 



The specimen from the southern portion of the Malacca Straits has about 

 140 arms. It is slightly smaller and has slightly fewer arms than the average from the 

 Philippines. The centrodorsal is rounded pentagonal, flush with the dorsal surface 

 of the radial ring, and bears a single cirrus which is 13 mm. in length and is composed 

 of 14 segments. The interradial areas are covered with a uniform fine calcareous 

 deposit which is not broken up into interradial plates. The synarthrial tubercles are 

 rather prominent. The dorsal surface of the animal as a whole is nearly flat. 



In the specimen from Billiton as described by Koehler there are no cirri, but the 

 remnants of cirrus sockets are still present on the periphery of the centrodorsal. 



One of the specimens from the Danish expedition to the Kei Islands station 67 

 has about 120 arms. The 10 IIBr series are all 4 (3 + 4). The outer IIIBr series 

 are 2 and the inner 4 (3 + 4) on all the postradial series. The centrodorsal is some- 

 what irregularly pentagonal and is not quite sunken to the level of the radial circlet; 

 it bears a few minute cirrus stumps. The interbrachial perisome is narrow and 

 completely plated. The other specimen is medium sized with about 85 arms. Of the 



