414 PROCEEDINGS OP THE ACADEMY OP [1881. 



Fig. 7. Teleiocrinus with traces of hydrospires, fig. a, portions of two 

 pairs of ambulacral tubes within the radiating tunnels beneath the 

 vault, exposing the upper or ventral side. Fig. b, transverse section 

 of the same, indicating two compartments along the tunnels, separated 

 by partition (pj, the upper containing the ambulacral tubes, the 

 lower the hydrospires. (Compare with fig. 8. ) 



Fig. 8. A pair of ambulacral tubes in Actinocrinus glans Hall, as seen 

 from the inner side. Their exit into the arm passages concealed by a 

 delicate partition (p), partly surrounding the tubes, and separating 

 them from the hydrospires ; the partition being evidently a continua- 

 tion of the delicate network which lines the inner floor of the vault. 

 The hydrospires are not preserved, but they probably rested, as in fig. 

 7, beneath the ambulacral tubes. AO represents the arm openings 

 seen from the inner side of the body. 



Fig. 9. Internal cast of the vault and free rays in Actinocrinus muUira- 

 diatus. The ridges radiating to the rays represent furrows at the 

 inner floor of the test. 



Fig. 10. Oesophageal network of Eretmocrinus Verneuilianus Shum. 



Fig. 11. The same organ in Teleiocrinus rudis Hall. 



Fig, 12. The same in Batocrinus, one convolution partly removed. 



Fig. 13. The same in a different species of Batocrinus. 



Fig. 14. A part of the same organ in OUacrinus tuberosum. 



Fig. 15. A portion of the network magnified. (From a specimen of 

 Actinocrinus glans.) 



Fig. 16. Batocrinus longirostris Hall. The test partly removed, exposing 

 to view the intervisceral plexus. 



Fig. 17. The oesophageal network seen from the base. 



