Ed. VI: 8 ) 
THE CRINOIDEA. 
13 
The joints of the pinnules, outside the widened ones, are fairly slender, smooth, 
the distal ones slightly thorny on the outer end (PI. II, Phg. 5; textfig. 11). The 
articulations are not swollen. 
A pair of curious abnormalities were observed. In one case the fourth pinnule 
has been doubled, a smaller extra pinnule developing at its base, but independent of 
it (Fig. 9); it is directed downward along the armside, and had the ambulacral furrow 
developed. The other case was a bifurcating pinnule; the bifurcating joint is the fourth. 
Some thin, irregular, fenestrated plates are developed along the borders of the 
ambulacral furrows (PI. II, Fig. 5); they represent the side- and coverplates, the latter 
being the larger. They are, however, not always so well developed; the side plates 
are often irregularly arranged, so that it is difficult to find the one corresponding to 
each coverplate; they may even be totally wanting. Also the cover plates 
may be reduced to a simple spicule, at intervals even totally disappearing. 
Spicules, in the shape of short, straight, thorny rods (Fig. 12) may occur 
in the tentacles, but very inconstantly; sometimes there may be quite a 
bundle of them in a single tentacle of a pinnule, the rest of them being 
entirely devoid of spicules. 
Sacculi generally fairly regularly developed on the pinnules, less so on 
the arms and apparently entirely wanting along the ambulacral furrows on 
the disk. They are very pale and inconspicuous in the preserved specimens. 
Disk naked. The mouth slightly eccentric; the anal cone nearer the 
oral corner of its interradius. The interradial areas may be quite narrow, 
pressed in by the cirri rising between the arms (PI. I, Fig. 10). 
Most of the preserved specimens are pure white. There are no indica- 
tions of the color in life. 
This species was taken at the following localities: 
Fig. 12. 
Spicules of 
tentacles of 
Isometra 
•vivipara. 
300 /z. 
Station 1 (33° o' S. 5110' W. 80 m.) 1 specimen. 
2 (37 50 S. 56° 1 1' W., Coast of N. Argentina, 100 m.) . . . . 1 
5 (64’ 20' S. 56’ 38' W., Graham region; SE. of Seymour Isl., 
150 m.) 3 specimens. 
» 5 a (64’ 20' S. 56° 38' W. 150 m.) i specimen. 
58 (52° 29' S. 6o° 36' W., Burdwood Bank, S. of Falkland Isl., 
197 m.) i » 
* 59 ( 53 ° 4 i ( S. 61 10' W., Burdwood Bank, 137 — 150 m.) .... 9 specimens. 
Dr. K. A. Andersson referred the present species to Antedon hirsuta P. H. 
CARPENTER. That it has nothing with that species to do was pointed out by A, H. 
CLARK (op. cit.), who referred it to his genus Isometra , thinking that it might pos- 
sibly be identical with the type species of that genus, I. angustipinna (P. H. Car- 
