OF THE SIBOGA-EXPEDITION, 141 
less developed third; of the outer columns six have three 
sockets, two have four and two have two. 
Type locality. — »Siboga” Station N°. 45. 
Psathyrometra minima, sp. nov. 
The centrodorsal is sharply conical, 1.8 mm. in diameter 
at the base and 1.6 mm. along the sides; somewhat irre- 
gular shallow grooves, averaging about half as wide as the 
cirrus-sockets, divide the sides of the centrodorsal into five 
radial areas; each radial area contains two columns of 
cirrus-sockets which are closely crowded together; each 
column contains usually two sockets (in one case only one), 
The arms are all broken at the first syzygy; the distance 
from the tip of the centrodorsal to the first syzygy is 
5.5 mm. 
Type locality. — »Siboga” Station N°. 48. 
Psathyrometra inusitata, sp. nov. 
This species is most closely related to Ps. congesta of 
Hawaii, but it is a much smaller form with a smaller and 
lower centrodorsal, much shorter segments in the proximal 
portion of the lower pinnules, and much less developed 
synarthrial tubercles. 
The centrodorsal is small, conical, the sides slightly 
if at all convex, the bare dorsal pole exceedingly small, © 
3.2 mm. in basal diameter and 2.4 mm. from the dorsal 
pole to the interradial border; five very narrow bare areas 
divide the sides of the centrodorsal into five radial areas; 
these at the base are rarely half as broad as the adjacent 
cirrus-sockets, and they are more or less encroached upon 
by the cirrus-sockets on either side so that their course 
may be more or less zigzag or irregular; they are scarcely 
to be made out except in that the outer columns of cirrus- 
sockets in each radial area are slightly separated from the 
outer columns in the next area, whereas in each area all 
Notes from the Leyden Museum, Vol. XXXIV. 
