ECHINODERMATA 239 
ciliated pores which traverse the integument. This system 
represents the stone canal of Asterids. In one species of 
Hm cob 
Fy 
v0. 
Fig. 141.—A longitudinal section through the plane of the mouth and anus of 
Pentacrinus decorus, Wyv. Th. After Carpenter. 
Mouth. 6,, 62, 63. First, second, and third radial 
Alimentary canal. plates. 
Anus. 7,;, 7g. First and second distichal 
On the left, the axial cord of the (brachial) plates. 
ray; on the right, extensions of 8. The more or less calcified connective 
nerves from the axial cord into tissue in the body-cavity. 
the plated perisome of the ventral 9. Central vascular axis of stem. 
side. 4;, ambulacral nerve. The 10. A cirrhus. 
central nervous mass is shown at 11. Genital rhachis. 
4, near the basal plate. 12. Ligament between the ray joints. 
Basal plate. 13. Radial water-vessel. 
The black plexus of blood-vessels in the centre of the figure is the plexiform gland, 
containing the genital stolon. 
Rhizocrinus there is one canal and one pore in each interradius, 
but the number is much increased in other Crinoids. 
The five genital strands are continuous with a central 
genital stolon, which here, as in Asterids, has been mistaken for 
a heart by German authors. Around this stolon are numerous 
vessels, which in the central capsule of the dorsal nervous 
