Plate 33. 



Fig. 1. Halitrephes maasi, gen. nov., sp. nov. Tentacle base, showing endodermio root 



(en.r). X 20. 

 Fig. 2. Halitrephes maasi, tentacle, showing differentiation into proximal and distal 



regions. X 5. 

 Fig. 3. Halitrephes maasi. Somewhat diagrammatic section through bell margin to 



illustrate relation of endodermal root of the tentacle (en.r) to circular canal 



(c.c) ; (v) velum ; (g) mesoglosa. 

 Fig. 4. Halitrephes maasi, oral view of type. The position of the gonads is indicated 



by the shaded areas at the bases of certain of the radial canals. Slightly 



more than natural size. 

 Fig. 5. Halitrephes maasi. Proximal portion of tentacle in optical section, to show its 



core of chordate endodermio cells ; (en) endoderm core. 

 Fig. 6. Homeonema alba, otocyst. From a photograph, x 250. 



Fig. 7. Halitrephes maasi. Tip of tentacle, closely crowded with nematocysts. X 30. 

 Fig. 8. Halicreas papillosum, otocyst ; (en) endodermic core. From a photograph, x 250. 

 Fig. 9. Halicreas papillosum. Segment of distal portion of tentacle with the ectoderm 



partly stripped off, showing the endodermio core. 

 Fig. 10. Halitrephes maasi, otocyst. x 150. 

 Fig. 11. Homoeonema alba; one octant of bell margin; (en.r) endodermio root of the 



large radial tentacles (t.ra) of which only the stumps persist ; (otc) otocyst. 



There are stumps of fourteen iuterradial tentacles. From a photograph, x 15. 



