7G0 
ZOOLOGICAL LITERATURE. 
the upper more transparent sarcode-hemisphere indicates the nascent tissues 
of the vault, and at a subsequent stage originates the ambulacral ring with its 
radial branches and the tissues of the young arms. From six to twenty-four 
hours later the pseudombryo becomes more sluggish in its movements, and 
begins to lose its characteristic contour. The anterior extremity beomes 
somewhat flattened, and then slightly depressed in the centre. The stem of 
the included crinoid lengthens, and tlie sarcode of the body of the pseudem- 
bryo contracts towards it. The pseudostome and pseudoproct become obscure 
and are shortly obliterated, the sarcode forming a thick, smooth, uniform 
layer over the stem and over its terminal disk. The two posterior ciliated 
bands disappear, the anterior bands remaining entire a little longer, and still 
subserving the locomotion of the pseudembryo. The anterior bands then 
likewise gradually disappear, the pseudembryo sinking in the water and rest- 
ing upon a sea- weed or a stone, to which it becomes finally adherent. 
Norman (/. c. p. 102) records the following as British : — Anteclon rosaceus 
(Linck), A. milleri (J. Miill.), A. sarsii (D. & K.), and A. celticus (Barrett). 
Pentacrinus. Liitken (/. c.) informs us : — 
There are three specimens of a recent species of the genus Pentacrinus in 
the Museum of the University of Copenhagen, which have been procured 
from time to time from the Danish West-Iiidian possessions. 
One of these specimens was briefly described by I’rof. Oersted in 1850, 
and distinguished by him from the Pentacrinus described by Johannes Miil- 
ler (P. asteria, L.). All the three Copenhagen specimens are to be referred 
to one form, P. miilleri (Oersted). 
. One of the most marked distinctions between P. asteria (L.) and P. miilleri 
(Oerst.) is, that in the former from 16 to 18 joints intervene between the cirri- 
gerous joints of the stem, while in the latter the number is reduced to from 
5 to 10. In P. asteria the peculiar pores between the stem-joints are con- 
tinued much further down the stem than in P. midleri. In P. asteria the 
cirrigerous joints are a little thicker than the ordinary joints of the stem, 
while in P. miilleri they are three or four times as thick. In the latter species, 
however, these joints are actually double, composed of Uvo joints more or less 
closely united together, the cirri being placed on the upper. Even in P. 
asteria there is a peculiarly close junction between the cirrigerous joint and 
that immediately beneath it. In P. miilleri the cirri are slightly toothed 
beneath towards the tips. 
In P. miilleri the basalia form a complete circle below the first radial, 
below the centre of each of which the short suture uniting the basals is very 
distinct. The second and upper radials are united by a syzygial suture, and 
not by a true joint. 
Perhaps the most prominent character of the new species is the mode of 
branching of the arms. The ten arms constantly bifurcate after the second 
joint; of these two primary branches the inner usually does not divide, 
whereas the outer again bifurcates over the third or fourth joint of the 
secondary branch. The outer again divides over the third joint into the ter- 
tiary branches, the inner remaining entire ; the outer of these may again 
bifurcate over the third or fourth joint into two quaternary arms. Thus in 
P. miilleri the outer arm only divides, but the bifurcation takes place more 
frequently and at shorter intervals than in P. asteria. Professor Oersted’s 
