LANUGONYCIIIA FLABELLUM. 
103 
E. Topsent’s description ( loc . cit., 1901, p. 36) the B. spinosus examined by him. 
resembles B. laevis F. E. Schulze and also Wilson’s subspecies B. laevis spinosus. 
Of all the descriptions cited, Wilson’s of B. laevis spinosus (loc. cit., 1904, p. 51) 
agrees best with the sponges here under discussion. The latter differ, however, 
from that subspecies, and also from B. laevis and B. spinosus, by the pentactines 
being generally densely covered with small spines. For this reason, and because 
there are also other, minor differences, I establish a new systematic unit for 
them, which should, I think, be a subspecies of Bathydorus laevis, equivalent to 
Wilson’s B. laevis spinosus. 
However should future studies prove, as seems probable, that Bathydorus 
laevis and B. spinosus are identical, the latter having priority, the name Bathy- 
dorus spinosus spinosissimus would prevail. 
The specific name of Bathydorus laevis is variously given as laevis and levis. 
Lanuginellinae F. E. Schulze. 
Rossellidae with plumicomes, but without discoctasters. 
The collection contains one specimen of this subfamily, a new species of the 
new genus Lanugonychia. 
LANUGONYCHIA, gen. nov. 
Rossellidae (Lanuginellinae) with onychhexasters, discohexasters, and plu- 
micomes. Without octasters. The superficial skeleton consists of hexactines 
in which all the six rays or only five, four, three, two or one are normally 
developed, the others being reduced to terminally rounded protuberances. The 
unreduced forms (true hexactines) preponderate in the gastral, the strongly 
reduced forms (hexactine-derivate diactines and monactines) are restricted to 
the dermal membrane. 
Lanugonychia flabellum, sp. nov. 
Plate 12, figs. 20-34; Plate 13, figs. 1-28. 
The unique specimen of this species was found northeast of Easter Island 
at Station 4695 on 23 December, 1904; 25° 22.4' S., 107° 45' W.; depth 3694 
m. (2020 f.) ; it grew on fine, light brown ooze. 
On account of its being fan-shaped I name it flabellum. 
Shape and size. The single specimen is somewhat fragmentary and macer- 
ated. It appears (Plate 13 , fig. 8) as a flat, elongated, irregularly triangular 
