PLATE V. 



The Convoluted Organ, and the structure beneath the Tegmen. 



Page 



Fig. 1. A specimen of Teleiocrinus, showing the convoluted organ, and portions of the 



ambulacral skeleton, both heavily coated with silicious matter (f) . 106, 143 



2. The same organ in Cactocrinus, showing the partition which forms the second 



convolution, the outer wall being removed . . 106 



3. A Teleiocrinus umbrosus, with the whole convoluted organ intact (slightly en- 



larged 143 



4. Another specimen of the same species, exposing the walls forming the third 



convolution, the two outer ones removed (slightly enlarged) . . . 106, 143 



5. The convoluted organ of an Agaricocrinus, seen from above 106 



6. Cross section of the same organ in a specimen of Batocrinus 106 



7. Dorsal aspect of the same organ in a specimen of Macrocrinus verneuilianus . 106 



8. Lateral view of the organ in M. verneuilianus ; its upper end surrounded by 



an annular vessel 105, 143 



9. The convoluted organ in a specimen of Strotocrinus 143 



10. Cactocrinus proboscidalis, showing a portion of the ambulacral skeleton, and 



the convoluted organ beneath 107 



11. Cactocrinus thetis, showing the delicate network of the convoluted organ . . 143 



12. Dorsal aspect of the organ in Eutrochocrinus Choistyi (enlarged) .... 143 



13. A broken specimen of Dorycrinus, showing the internal lining and covered 



galleries along the inner floor of the tegmen 106, 107 



14. The inner floor of the tegmen in a Physetocrinus ventricosus 120 



15. A broken specimen of Lobocrinus longirostris, showing the lining within the 



dorsal cup 106 



16. The inner floor of the tegmen of a specimen of Teleiocrinus ruclis ; heavily 



coated with silicious matter 106, 107 



17. The inner floor of Batocrinus inornatus, formed into open galleries for the 



reception of the ambulacra 106 



(All specimens are in the collection of Wachsmuth and Springer, except 

 those of Figs. 10, 11, and 15, which are in the Museum of Comparative 

 Zoology.) 



