324 p. HERBEET CARPENTER. 



termine inferieurement en un tube conique qui penetre en 

 s'amincissant toujours^ dans I'axe de I'organe cloisonne/'' 



This connection was described by Ludwig seven years ago in 

 An ted on and Rhizocrinus; and I have since stated that I 

 had been able to confirm his observations in both these types, 

 and had extended them toActinometra, Pentacrinus, and 

 Bathycrinus. One would think, however, from what Perrier 

 says, that he was describing an entirely novel observation. At 

 auy rate, I am glad to find him admitting that this axial organ 

 is the upward continuation through the chambered organ of a 

 structure which runs down the larval stem as a '^ cordon 

 central" with five ^'cordons peripheriques ^^ around it; and 

 that the latter enlarge at the top of the stem to form the five 

 cavities of the chambered organ. Considering the minute size 

 of these cordons in the stem of the Pentacrinoid, one could 

 hardly expect them to possess a lumen. But the case is very 

 diff'erent in the stalked Crinoids. Ludwig long ago described 

 and figured the six vessels, one cential and five peripheral, in 

 the stem of Rhizocrinus; and I have mentioned their pre- 





'^U- 



r?-?. 



J^ 





'MliBf^^ "'■ 



Tig. 1. — The central part of a horizontal section through a nodal joint in the 

 stem of Pentacrinus. x 90. c. Central vessel, p. Peripheral 

 vessels, expanded into miniature " chambers." c.v. The cirrus-vessels 

 proceeding from these clambers. / Fibrillar sheath of the vascular axis. 

 I. The interradial tendons of the stem. s. Organic basis of the skeleton. 



