260 G. HERBERT FOWLER. 



Fig. 3. — View of half of the corallum of Flabellum, showing the 

 relations of pedicle, theca, and septa, and the incomplete 

 union of the septa marked x, in Fig. 1, into a columella. 



Fig. 4. — Portion of the lip of the calyx of Flabellum, viewed from 

 the exterior by transmitted light, to show the grooves, 

 i, ii, iii, corresponding to the septa of those orders, with 

 the lines of growth of the theca curving upwards at those 

 points. 



Fig. 5 . — Primary mesentery and base of primary tentacles of Flabel- 

 lum, showing the direction of the muscles, contortions of 

 the free edge omitted. 



Fig. 6. — Section along the line a, Fig. 2, from a full-grown specimen, 

 with the layer of calycoblasts between mesoderm and theca. 



Fig. 7. — Similar section through the internal body- wall of a younger 

 polyp, in which the calycoblasts are much better marked. 



Fig. 8. — Section through the tissues clothing the septum of a young 

 Flabellum. 



Fig. 9. — Section through the wall of a tentacle, including one com- 

 plete "battery." 



Fig. 10. — Section through a mesenterial filament of Flabellum. 



Fig. 11. — Transverse section through part of a mesentery, to show 

 the mesodermal pleatings on which lie the muscles. 



Fig. 12. — Transverse section of an acontium of Flabellum. 



Fig. a. Transverse diagrammatic section of Caryophyllia (after v. 

 Koch), a. Septa, b. Mesenteries. 



Fig. b. Similar section through Caryophyllia, in a lower plane than 

 a (after v. Koch), a. Septa. U. Central, V. peripheral 

 parts of the mesentery, c. Costa, th. Theca. 



Fig. 13. — Diagram of a longitudinal section of Bhodopsammia, con- 

 siderably shortened in the longer axis ; the right half of 

 the figure taken along the lines c. c. in Figs. 14 and 15, 

 i.e. in an exoccele ; the left along the lines d. d. in the 

 same figures, and therefore cutting through a septum and 

 a tentacle, c. Cut edge of external body-wall. d. Cut 

 edge of tissues clothing theca and columella. B. Tissue 

 clothing the entoseptum, which is seen projecting from 

 behind the mesentery. On the left side the inner face 

 of a mesentery (m) is seen similarly projecting from behind 

 the septum. The costse being in this form rows of spines, 

 appear as projections in both transverse (Fig. 14) and 

 longitudinal (Fig. 13) sections. 



