18 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



P 2 and P 3 of up to 14 segments and 10 mm. long; the other pinnules of 30 segments and 

 18 mm. long. 



In most of the specimens the disk between the rays and the arm bases is completely 

 covered with rather large thin plates. The walls of the pouches containing the repro- 

 ductive organs are not studded with plates as in N. virilis; they are thin and trans- 

 parent. The largest number of embryos taken from one brood pouch of a female was 45. 



Dr. John also noted that the arms taper rapidly from the base to the tips. The 

 surfaces of the ossicles of the division series, and of the brachials and pinnulars of 

 young specimens are uniformly beset with stout triangular spines. Older specimens 

 are similarly covered but the spines are shorter and finer, especially on the more proximal 

 ossicles, and give rise to a granular appearance. 



The B.A.N.Z.A.R.E. took a single pcntacrinoid which Dr. John deduced was of 

 N. mortenseni. It has only four columnals remaining. The first two are short and 

 discoidal, the second not so wide as the first. The third is narrower than the second 

 and about half as long as wide. The crown is 4-5 mm. long, the arms being of 11 or 

 12 brachials and curled in at the ends. The basals are shorter in relation to the radials 

 than they are in far larger pentacriuoids of TV. virilis. The basiradial cup is wide 

 and with rounded sides, as in young pentacrinoids of N. virilis. The basals and radials 

 are of about equal length. The latter are in contact with one another, forming a 

 complete circlet. Their distal borders are not incised for the articulation of the IBi'i. 

 The orals are separated from the radials by narrow strips of naked perisome. The 

 radianal is an oval plate resting on the posterior oral, and at one point touching 

 the IBri of the right posterior ray. There are no pinnules. The ambulacra of the 

 arms are lined by large plates. The texture of the stereom of all the ossicles is 

 particularly loose and, as a consequence, their surfaces are very rough and thorny. 



Parasite. Some myzostomes were found on the genital pinnules of the types. 



Localities. Discovery Investigations station 1948; east of Clarence Island (lat. 

 6049'24" S., long. 5240' W.) ; 490-610 meters; January 4, 1937 [John, 1938] (1, 

 B.M., now selected as the lectotype). Type locality. 



Discovery Investigations station 170; off Cape Bowles, Clarence Island (lat. 

 6125'30" S., long. 5346' W.); 342 meters; bottom, rock; at 335 meters, temperature 

 -0.42 C., salinity 34.47% ; February 23, 1927 [John, 1938] (2, B.M.). 



Discovery Investigations station 187; Neumayr Channel, Palmer Archipelago (lat. 

 6448'30" S., long. 6331'30" W.); 259-354 meters; bottom, mud; March IS, 1927 

 [John, 193S] (1, B.M.). 



Discovery Investigations station 190; Bismark Strait, Palmer Archipelago (lat. 

 6456' S., long. 6535' W.) ; 315 meters; bottom, mud and rock; at 300 meters, tempera- 

 ture 0.55 C., salinity 34.49% ; 100-130 meters; bottom, mud, stones and rock; at 

 100 meters, bottom temperature 0.31 C., salinity 33.89% ; March 24, 1937 [John, 

 193S] (2, B.M.). 



B.A.N.Z.A.R.E. station 30; off Princess Elizabeth Land (lat. 6648' S., long. 

 7124' E.); 540 meters; December 27, 1929 [John, 1939] (3, B.M.; 5, Australian Mus.). 



B.A.N.Z.A.R.E. station 34; off Kemp Land (lat. 6621' S., long. 5850' E.); 603 

 meters; January 6, 1930 [John, 1939] (1, B.M.; 1, Australian Mus.). 



B.A.N.Z.A.R.E. station 40; off Enderby Land (lat. 6612' S., long. 4937' E.); 

 300 meters; January 17, 1930 [John, 1939] (2 adults, 1 pentacrinoid larva, B.M.; 3, 

 Australian Mus.). 



