174 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Syzygies occur between brachials 3+4, again between about brachials 14+15, 

 and thence at very irregular intervals. 



P! is relatively large with about 20 segments of which the lowest are broad with 

 strong dorsal keels and flattened outer sides. P a is similar but rather smaller. P z 

 and Pt, are much smaller and are but slightly cariuate. The pinnules following in- 

 crease slowly hi length and at about the twentieth brachial they become boat-shaped 

 at the base owing to the expansion of the third and next few segments. 



The disk is 6 mm. in diameter, rather incised and much plated, as are also the lower 

 parts of the arms. The pinnule ambulacra have fairly well developed side plates, but 

 the sacculi are small and rare. 



The color in alcohol is brownish white. 



Notes. The preceding description is adapted from that of Carpenter, with a few 

 additions by Gislen. This is a slender species, about the build of Th. attenuate, though 

 more robust basally. 



Carpenter called attention to the fact that in this species P a is of the same type as 

 PI, smaller in size but with similarly carinate lower segments which are flattened on 

 the outer side. He said that the fringe of small spines on the elements of the IBr series 

 and lower brachials rather obscures their straight-edge and wall-sided character, though 

 this is very distinct in the smoother individuals, and the lateral flattening of the basal 

 segments in PI indicates the position of the type very clearly. 



He said that the pinnules beyond the twentieth brachial until near the end of the 

 arms are remarkable for the character of the third and following segments which are 

 widely V-shaped in cross section so that the lower part of the pinnule has a boat-shaped 

 appearance when seen from the dorsal side. This expanded portion of the pinnule 

 encloses the gonad, and according to Carpenter recalls on a smaller scale a similar 

 arrangement in the pinnules of Hyocrinus. The enlargement of the lower segments of 

 the pinnules gradually disappears toward the ends of the arms and there is no indication 

 of it hi the pinnules of the youngest individual obtained. 



This young individual shows much more of the radials externally than is visible in 

 the adults, while P a shows hardly any trace of the enlarged and carinate basal segments 

 which appear in the adults. 



A specimen from Albatross station 4919, which does not appear to differ in any 

 tangible features from Carpenter's Antedon gracilis, was described as a new species 

 under the name of Antedon pubescens. Its characters are as follows: 



The centrodorsal is rather small, bluntly conical. The cirrus sockets are arranged 

 in 10 columns of usually three each. 



The cirri are XXV-XXX, 50-55, slender, 30 mm. long. The proximal 10 or 12 

 segments beyond the basal are longer than broad, and the distal are broader than long 

 and develop rather low dorsal spines. 



The ends of the basal rays are just visible in the interradial angles of the calyx 

 as small tubercles. 



The radials are visible in the interradial angles over the ends of the basal rays. 

 The IBri are short and bandlike, sharply carinate, with raised and serrate edges. The 

 IBr 2 (axillaries) are low and broad with a sharp keel in the proximal half. 



The 10 arms are 80 mm. long. The first 6 or 7 brachials are oblong, those folio whig 

 wedge-shaped, becoming elongate distally. The elements of the IBr series and lower 



