514 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



progressively elongated. The fifth to ninth segments bear a long fusiform gonad. The 

 following pinnules resemble P 3 , becoming gradually shorter and then longer again 

 distally. The distal pinnules are about 15 mm. long with the first segment very short, 

 the second trapezoidal about as long as the greater (basal) width, and the third and 

 following about twice as long as broad, becoming rather more elongate distally. These 

 pinnules are slender, in this respect resembling P, and P 2 . 



Notes. In 1908 I described 2 additional species of Psathyrometra, both of which I 

 now believe to be identical with Ps.fragilis, as indicated in my memoir of 1937 on the 

 crinoids of the Okhotsk and Japan seas. These were described wholly in terms of 

 the centrodorsal. 



In Psathyrometra borealis the centrodorsal was given as long conical, 6 mm. long 

 and 5 mm. broad at the base, with the bare interradial lines as wide as, or slightly 

 wider than, the columns of cirrus sockets and continued to the dorsal pole. The 

 cirrus sockets are in 3 columns in each radial area, from 7 to 9 to a column, the 

 columns within each radial area being separated from each other by narrow lines. 



In the type of Ps. borealis the cirri, none of which are preserved for more than 

 two-thirds of their length, seem to be identical with those of Ps. fragilis. 



The posterior projection of the axillaries is rather stronger than in the type of 

 fragilis, and the earlier brachials have traces of articular tubercles. 



P! is 16 mm. long. P 2 is 14 mm. long. P 3 is 17 mm. long. P 4 is 16 mm. long. 

 P 6 is 17 mm. long. P 6 is 18 mm. long. These pinnules resemble the corresponding 

 pinnules in the type of fragilis, and as in that specimen P, and P 2 are rather more 

 slender than P 3 . 



The distal portion of the arms is lacking. 



In Psathyrometra pro/undorum the centrodorsal was described as long conical, 7 

 mm. long by 4.5 mm. broad at the base, the interradial lines being basally about half 

 as broad as the cirrus sockets and apically become obsolete. There are 3 closely 

 crowded columns of cirrus sockets in each radial area, 6 sockets to a column, the edges 

 of the sockets being very prominent, especially the proximal edges. 



On the arms the synarthrial and articular tubercles are especially well developed. 



The radials, division series, and arm bases resemble those of the type of Ps. 

 fragilis, but are rather more slender and delicate, though with the posterior projection 

 of the axillaries and second brachials more developed. 



P! is 16 mm. long with about 18 segments, of which the first is about twice as 

 long as broad and the following become progressively elongated and exceedingly long 

 and slender distally. P 2 is similar, 14 mm. long. P 3 is 13 mm. long and slightly 

 stouter than the two preceding pinnules. 



In a series of 11 specimens from Albatross station 4230, which at first I considered 

 as representing a new species (alascana), the centrodorsal varies from a broadly 

 truncated cone not much higher than wide at the base to very elongate, half again 

 or more as high as broad. The cirrus sockets may be arranged in 3 regular and 

 well-spaced columns as in the type of borealis, in 3 closely crowded columns as in the 

 type of profvndorvm, or in 4 closely crowded columns as in the type of fragilis. 

 There are frequently 3 regular columns with a greater or lesser number of additional 

 cirrus sockets between them. 



In a series of 57 specimens from Albatross station 4537 the centrodorsal shows 

 much variation in length. The number of columns of cirrus sockets in each radial 



