118 THREE CRUISES OF THE “BLAKE.” 
mens the cirri of which had become attached to adjoining stems. 
It is possible that they may live gregariously, more or less united 
either by the twisting of the stems or the grappling of the cirri, 
and be only loosely attached to the ooze on which they live, or 
anchored more securely by the terminal whorl to some project- 
ing piece of rock or gorgonia stem. 
Crinoids both stalked and free live in colonies. Comatule 
are most abundant in certain local- 
ities. Antedon Sarst was brought 
up in thousands by the “ Blake.” 
The U. S. Fish Commission and 
the “Challenger " have had a sim- 
ilar experience with different spe- 
cies of Comatule. On one occa- 
sion, off Sand Key, we must have 
passed over a field of Rhizocrinus 
with the dredge, judging from the 
number of stems and heads of all 
sizes it contained. The oldest species 
known, Pentacrinus asterius (Fig. 
405), is marked by its greatly mul- 
tiplied large and strong arms, while 
in P. decorus (Fig. 407) the num- 
ber is greatly reduced. We know 
but little of the young of Pentacri- 
nus. The youngest specimens 
dredged by the “ Blake," and fig- 
See tur N 
x mer nm A TS 
AA el 
ona ee i m 
TN a ured by Carpenter (Fig. 408), show 
ug a the great relative height of the stem 
Fig. 408. — Pentacrinus decorus, 4. Joint as a characteristic feature of 
(Carpenter. young specimens. The stems of 
Pentacrinus asterius and P. decorus are longer than those of 
the other species of the genus. P. Mülleri (Fig. 409) was dis- 
covered by Oersted, and in 1865 Dr. Lütken gave a detailed 
account of the West Indian Pentacrinide; the many speci- 
mens of Pentacrinus dredged by the * Blake" were originally 
identified with it, but, as has been clearly shown by Carpenter, 
they all belong to P. decorus. Both P. Mülleri and P. 
