REPORT ON THE CRINOIDEA. 109 
the cavity with its granular contents bears a smaller proportion to the thickness of the 
tubular wall. I suspect that this varies soméwhat according to the sexual maturity of the 
individual ; but I have generally noticed that the vessels of this plexus in Antedon eschrichti 
do not show such a clear section as the visceral blood-vessels, their lumen being occupied 
by cellular structures; while in some disks of this species I have found as distinct a 
genital tube within the vessels of this subambulacral plexus as is to be met with in the 
arms between the bases of two successive pinnules. 
Further, in one example of Antedon rosacea, 1 found a small but well-developed ovary 
occupying the position of the genital plexus beneath the left posterior ambulacrum of the 
disk. The first traces of it appear in the sections which pass through the hinder part of 
the spongy organ ; and it extends outwards to the point where the primary radial groove 
divides into the two which proceed to the arms. It contains the nuclei of half a dozen 
ova in various stages of development, some with a germinal spot, and some without. 
A still larger and more fully developed ovary oceurs in the disk of one of the three 
examples of Actinometra pulchella which I have cut into sections. It commences close 
to the peristome, and extends outwards beneath the left anterior ambulacrum nearly to 
its bifurcation, lying close down upon the upper surface of the intestine, and moulded to the 
plications of its wall. 
In Antedon carinata I have not only found a distinct genital tube within some of the 
vessels forming the plexus beneath the disk ambulacra, but I have also met with detached 
portions of ovaries containing more or less fully developed ova in various parts of the 
body-cavity, e.g., in the spaces of the connective-tissue network forming the lip ; in the 
intervisceral portion of the body-cavity, between the two parts of the coiled gut; and in 
the subtentacular canals between the genital plexus and the water-vessels. 
There can, therefore, I think, be hardly any question as to the relation between the 
genital glands and portions of the blood-vascular system ; while the occasional develop- 
ment of rudimentary ovaries within the disk of recent Crinoids is of considerable 
importance. For it shows that there is no morphological improbability in the theory which 
supposes the genital glands of extinct armless types, like the Blastoids and Cystids, to have 
been situated within the body, rather than in the so-called pinnules, even when these are 
present, which is by no means always the case. 
The fertile intra-pinnular portions of the genital glands vary considerably in shape. 
In most of the British varieties of Antedon rosacea, in Antedon angusticalyx, Antedon 
acoela, and Eudiocrinus japonicus, they are short, thick, and rounded. They some- 
times terminate in rounded ends, and are sometimes continued onwards as slender cords 
through two or three pinnule-joints. But in the Antedon rosacea from Naples, and in 
the group of species allied to Antedon eschrichti, they are long and fusiform, extending 
over several pinnule-joints. The same is the case in Hyocrinus (Pl. Ve. figs. 8, 10, 2), 
Bathyerinus (Pl). VII. fig. 7; Pl. VIII. fig. 5), and Fhizocrinus (Pl. X. fig. 20), though to 
