REPORT ON THE CRINOIDEA. 109 



the cavity with its granuhir contents bears a smaller proportion to the thickness of the 

 tubular wall. I suspect that this varies somewhat according to the sexual maturity of the 

 individual ; but I have generally noticed that the vessels of this plexus in Antcdon eschricJiti 

 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, I found a small but well-developed ovaiy 

 occupying the position of the genital plexus beneath the left posterior ambulacinam 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 occurs in the disk of one of the three 

 examples of Actinomctra lyuldiella 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 Y\-all. 



In Antedon carinata 1 have not only found a distinct genital tube wdthin 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 netw^ork 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 betw^een 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 angitsticali/x, Antedon 

 acoela, and Eudiocrinus japonicus, they are short, thick, and rounded. They some- 

 times terminate in rounded ends, and are sometimes continued onw^ards as slender cords 

 through two or three pinnule-joints. But in the Antedon rosacea from Naples, and in 

 the group of species aUied to Antedon eschrichti, they are long and fusiform, extending 

 over several pinnule-joints. The same is the case in Hyocrinus (PL Vc. figs. 8, 10, t), 

 Bathjcrinus (PL YII. fig. 7; PL YIII. fig. 5), and Rhizocnnus (PL X. fig. 20), though to 



