Bd. VI: 8) THE CRINOIDEA. 23 



Fig. 3. Proximal part of an arm of a male specimen, ventral a.spect; showing the swellings 

 produced b)- the testes, and the small genital pores in the corner between the pin- 

 nule and the ambulacral furrow. The lower pinnules are without an ambulacral 

 furrow. ^,1. 

 » 4. Part of an arm of a male specimen; the skin pardy prepared off so as to show the 

 shape and size of the testes. ' i. 



Plate IV. 



All figures of A'otocriniis virilis. 

 Fig. I. Section through a genital pinnule of a young female specimen; showing the mar- 

 supium just forming as an ectodermic invagination. In the ovary is seen a small 

 parasitic organism in longitudinal section. Only young eggs seen in the ovary. ° i. 



s 2. Section through a genital pinnule in a somewhat more advanced stage; the marsu- 

 pium considerably widened. The ovary contains a number of ripe eggs. '*' i. 



» 3, Section through the ovary of a grown specimen; showing the o]jening in the wall 

 separating the ovary from the marsupium. ■•* i. 



s 4. Part of a longitudinal section through an arm of a ripe female. In the middle of 

 the figure is seen, under the ambulacral furrow of a pinnule, a marsupium with its 

 external opening; in the marsupium are seen two embryos in transverse section. 

 Immediately behind the marsupium lies the ovary in the genital canal, separated 

 from the marsuijium only by a quite thin wall. The little space under the genital 

 canal represents the dorsal coelomic space or ' coeUac canal«. At the right side of the 

 figure is seen part of the marsupium of the foregoing pinnule, at the left side part 

 of the ovary of the following pinnule, separated only by a thin wall from the 

 marsupium and ovary of the neighbouring pinnule. ^'- 1. 



'" 5. Section through a young male genital pinnule. The genital pore (p) about to 

 form. ^°'r. 



Plate V. 



All figures of Thaumatometra niitrix. 

 Fig. I. The type specimen, dorsal aspect. On one of the arms to the left is seen a genital 

 pinnule with a large Pentacrinoid with its cirri developed, but with the arms broken 

 off; only one arm is hanging at the calyx of the Pentacrinoid, but not in its natural 

 position. " I. 



» 2. A genital pinnule with an egg in the marsupium. ^Vi. 



» 3. A genital pinnule with a young Pentacrinoid attached to the very edge of the mar- 

 supium, ^^'i. 



» 4. A genital pinnule with a young Pentacrinoid protruding through the opening of the 

 marsupium, attached to a pinnule joint. ^ i. 



» 5- A genital pinnule with two Pentacrinoids, in a more advanced stage, protruding 

 from the marsupium; they are attached to the third pinnule joint. ^U. 



» 6. A full grown Pentacrinoid, attached to the third joint of the genital pinnule. The 

 arms broken, only one of them remaining in situ. In the ovary the eggs are seen, 

 this figure having been drawn from a preparation in Canada-balsam, ^'/i. 



» 7. Section through a genital pinnule; showing the marsupium (m) on the side of the 

 ovary, '''/i. 



