CRINOIDEA—CLARK. 7 
Among the stalked crinoids the genus Ilycrinus (family Bourgueticrinidae) is 
found, in very deep water, only in the extreme north and south—from Enderby Land 
to the Crozet Islands (australis A. H. Clark), in the cold deeps north of Iceland and the 
Faeroe Islands (carpenterii Danielssen and Koren), and in the north Pacific from south- 
eastern Alaska to the Commander Islands (complanatus A. H. Clark). 
The unstalked crinoids or comatulids which occur in the Antarctic in less than 
600 fathoms may be differentiated by means of the following key. 
II.—KEY TO THE UNSTALKED CRINOIDS 
(COMATULIDS) OF THE ANTARCTIC. 
a! Ten rays and 20 arms (small specimens may have less than 10 rays, but 
never less than 6 rays, with twelve arms)... BE ae oe ... Promachocrinus kerguelensis. 
a® Five rays and 10 arms— 
b First pinnule (P,) composed of very short segments, few or none of 
which are longer than broad. 
c! Proximal pinnules shorter than those following, and P, shorter 
than P,; dorsal perisome between the arm bases heavily and 
completely plated; ventral surface of. the disk with very 
numerous plates, especially in the anal area; colour in life 
crimson, red-brown or brown when preserved... as ..» Notocrinus virilis. 
c Proximal pinnules longer than those immediately following; 
P, longer than P,, or P, and P, of the same length and longer 
than P,; dorsal perisome between the arm bases and ventral 
surface of the disk wholly without plates; colour in life yellow, 
of flesh colour with the pinnules pink, never crimson. 
d! Elements of the division series and brachials with a con- 
spicuous and usually high narrow median keel; segments 
of P, from the base to the tip with high carinate processes 
on the outer side; P, much shorter than P, and composed 
of segments most of which are much longer than broad; 
in life flesh coloured with the pinnules pink ... Sa: ... Anthometra adriant. 
d? Elements of the division series and brachials without high 
and narrow median keels; P, of about the same length as 
P,; in life bright yellow. 
el Large and robust, the arms about 125 mm. long; P, with 
about 60 segments; cirri with about 40 segments, most 
of which are not longer than broad; brachials beyond 
the third syzygy short, much broader than the length 
of the longer side; dorsal surface of the brachials before 
the third syzygy smooth ... nc a rt ... Solanometra antarctica. 
e? Smaller and more slender, the arms not more than 
85 mm. long; P, with not more than 36 segments; 
cirri with not more than 30 segments, those in the 
proximal two-thirds (except the basal) much longer 
