767 
of Edinburgh, Session 1871 - 72 . 
stem before becoming free. The cirri are much shorter than in 
P. asteria. The syzygy is between the two modified joints. In 
all complete specimens which I have seen, the stem has evidently 
been separated for long at one of these syzygies. I described some 
years ago a specimen in which this was the case, and suggested 
that in that instance the animal had lived for some time free. 
I have since seen several other examples in the same condition, 
and I believe that the disengagement at a certain stage of growth 
is habitual. The arrangement of the joints and syzygies in the cup 
is the same in P. mulleri as in P. asteria , only the syzygy between 
the second radial and the radial axillary is not so complete. The 
arms are more delicate, and appear never to exceed thirty in num- 
ber. The number of syzygies is very variable; sometimes they are 
confined, as in P. asteria, to the first joint after a bifurcation, and 
sometimes they occur at intervals all along the arms. The struc- 
ture of the disk is the same as in P. asteria , but its texture is more 
delicate, and the calcareous pieces are smaller and more distant. 
On the 21st of July 1870, Mr Gwyn Jeffreys, dredging from 
the <{ Porcupine,” at a depth of 1095 fathoms, latitude 39° 42' N. 
long. 9° 43' W., with a bottom temperature of 4°-3 0., took about 
twenty specimens of a handsome Pentacrinus involved in the 
hempen tangles attached to the dredge. 
1. P. wyville-thomsoni , Jeffreys. 
This species is intermediate in some of its characters between 
P. asteria and P. mulleri , it approaches the latter however most 
nearly. In a mature specimen the stem is about 120 mm. in 
length and consists of five to six internodes. The whorls of cirri 
towards the lower part of the stem are 40 mm. apart, and the 
internodes consist of from thirty to thirty-five joints. The cirri 
are rather short, and stand out straight from the nodal joint 
or curve slightly downwards. There are usually eighteen joints 
in the cirri, the last forming a sharp claw. As in P. asteria 
the nodal joint is single, and a syzygy separates it from the 
joint immediately beneath it which does not differ materially in 
form from the ordinary internodal stem-joints. All the stems of 
mature examples of this species end inferiorly in a nodal joint 
surrounded by its whorl of cirri, which curve downwards into a 
