564 BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



ninth, which, like the preceding, is cylindrical, the segments begin to show a 

 median constriction and swollen ends ; in the distal half of the column this feature 

 becomes very strongly marked. 



The terminal stem plate, which is attached to a small bivalve, is produced into 

 three long bifurcated digitiform processes and a broad irregular digitiform mass, 

 which occupies nearly one-half of its circumference. 



The lowest cirri, about the apex of the centrodorsal, are composed of 10 

 segments. They are radial in position and reach about to the second brachial. 

 Beyond these there is an irregular band of cirri, of which the lowest resemble the 

 apical and the uppermost, which are the longest cirri present, reach to the ninth 

 brachial or slightly beyond, and are composed of 11 or 12 segments. About the 

 proximal edge of the centrodorsal in the interradial angles are some rudimentary 

 cirri. 



The crown resembles that of the youngest free-living examples. The distal 

 angles of the IBr a , the lateral angles of the IBr 2 , and the distal edges of the 

 brachials are armed with prominent spines. 



All the pinnules are present. 



A specimen dredged by the Albatross on August 22, 1884, between Cape 

 Hatteras and Nantucket, in 428 fathoms, is badly mutilated, most of the arms 

 and column and all of the cirri being lost. 



Apparently it is in the same stage as the one just described. 



The centrodorsal is low conical, its truncated tip resting in the center of the 

 very thin columnal following, which is somewhat broader than the base of the 

 centrodorsal and pentalobate, the lobes being directed interradially. 



HATHROMF.TRA SAKSII. 



Figs. 121&-1225, pis. 35, 36 ; and part 1, figs. 407, 413, p. 317 ; pi. 2, fig. 530, and pi. 3, firs. 534, 536, 



537, 539-542. 



In 1856 Prof. Michael Sars communicated to the congress of Scandinavian 

 naturalists assembled at Christiania a brief account of the pentacrinoid young of 

 Hathrometra sarsii. 



Later he obtained 32 additional pentacrinoids in different stages of develop- 

 ment, which he described in great detail in 1868. Thirty-one of these penta- 

 crinoids were dredged by his son, Prof. George Ossian Sars, at different localities 

 in the Lofoten Islands, between 100 and 300 fathoms, at various times between 

 the beginning of March and the middle of July, and one was secured by him- 

 self in March at Manger, near Bergen, at a depth of 50 fathoms. 



The youngest specimen was captured at the beginning of July at Brettesnaes 

 in the Lofoten Islands, at a depth of 100 to 200 fathoms. It was attached to the 

 stalk of a Rka~bdopleura mirabilis growing on the column of a Rhizocrinus lofotensis. 



The total length was 4 mm., the column measuring 3.5 mm., and the calyx 

 a little less than 0.5 mm. 



In the stem there were 18 columnals, of which the two or three proximal were 

 almost spherical, or rather lenticular, being slightly compressed along the axis of 



