120 
THREE CRUISES OF THE “BLAKE.” 
smooth stem, with a rounded pentagonal outline; it is appa- 
rently not common, having been dredged by the * Blake " only 
at four localities. 
Rhizocrinus (Fig. 411) has a stem composed of dice-box 
shaped joints, terminating in a spreading root or a number of 
branching radicular cirri, not arranged in definite whorls, with 
a high calyx. 
described it, in 1868, as belonging to the Apiocrinide. 
It was first named by M. Saxs, who afterwards 
But 
before the appearance of Sars's memoir, this interesting crinoid 
had been rediscovered by Pourtalès, and stated by him to belong 
undoubtedly to the genus Bourgueticrinus of D'Orbigny, and 
he gave it the provisional name of B. Hotessieri, thinking it 
might prove identical with a crinoid of that name of which 
fragments had been found in the recent limestones of Guade- 
loupe. 
Pourtalés was the first to make out accurately the com- 
position of the cup, and he of course also recognized its identity 
with the Rhizocrinus of Sars’s memoir, R. lofotensis. 
Rhizo- 
crinus has been dredged by the Porcupine, the Hassler, the 
oms, from disintegrated coral rock bot- 
tom, up came six beautiful ‘sea lilies.’ 
Some of them came up on the tangles, 
some on the dredge. They were as brit- 
tle as glass. The heads soon curled over, 
and showed a decided disposition to drop 
off. At a haul made soon after we got 
more, and, being afraid to put so many of 
them in the tank together, I tried to 
delude the animals into the idea that 
they were in their native temperatures 
by putting them into ice-water. This 
worked well, although some of them be- 
came exasperated and shed some of their 
arms. They lived in the ice-water for 
two hours, until I transferred them to 
the tank. They moved their arms one 
at a time. Some of the lilies were white, 
some purple, some yellow ; the last was 
the color of the smaller and more deli- 
cate ones.” 
I have nothing to add to the general 
description of their movements given by 
Sigsbee, with the exception of their use 
of the cirri placed along the stem. These 
they move more rapidly than the arms, 
aud use them as hooks to cateh hold of 
neighboring objects ; and, on account of 
their sharp extremities, the cirri are well 
adapted to retain their hold. ‘The stem 
itself passes slowly from a rigid vertical 
attitude to a curved or even drooping po- 
sition. We did not bring up a single 
specimen that showed the mode of attach- 
ment of the stem. Several naturalists, 
‘on the evidence of large slabs contain- 
ing fossil Pentaerini, where no basal at- 
tachment could be seen, have come to 
the conclusion that Pentacrini might 
be free, attaching themselves tempora- 
rily by the cirri of the stem, much as 
Comatule do. Iam informed, however, 
by Captain E. Cole, of the telegraph 
steamer * Investigator," that he has fre- 
quently brought up the West Indian tel- 
egraph eable with Pentaerini attached, 
and that they are fixed, the basal extrem- 
ity of the stem spreading slightly, some- 
what after the manner of Holopus, so 
that it requires considerable strength to 
detach them. 
