97 



corallites frequently grow together, but, as in D. ingens, there is 

 no trace of any connection, either former or present, between 

 their polyps. It is in certain cases possible, however, that the 

 lateral polyps may have arisen by budding at the edge-zone of 

 the central polyp, but there is in some cases a little ridge, where 

 presumably the edge-zones of the two neighbouring polyps met 

 one another, while in other cases there may have been a fusion 

 of the edge-zones, as commonly occurs in other corals. 



The deposition of exotheca, shown by Moseley in D. ingens 

 (erroneously termed epitheca, see PI. IV., fig. 4a), has been car- 

 ried to a much greater extent in the present form, at the base of 

 one corallite where the edge-zone spreads out, a thickness of 

 over I cm. being visible. It is to some extent due to this deposi 

 tion that the corallites have not got that trumpet appearance 

 found in D. ingens. At the base of one of the type specimens 

 ol D. ingens in the British Museum endothecal dissepiments art^ 

 distinctly recognisable. This, too, is the case in D. capense, 

 where they are ratlier irregular (2 — 5 mm. apart), straight or 

 more or less curving, more closely set near the theca. They 

 may be almost absent, and in no case are visible from the sur- 

 face ; they never cross the axial fossa, and only deep down (2 cr 

 3 cm.) extend out for more than a milHmetre or two from the 

 theca. 



The septa have entire edges, a little thickened at the base of 

 the axial fossa, and are smooth-sided, with little or no trace of 

 ridges. 



Eight corallites, forming five specimens, from Cape Hangklip, 

 S.E. \ E., 71^ miles. Depth, 44 fms. Bottom, fine sand and mud. 

 (Refer. No., 15549.) 



Genus FLABELLUM (Lesson). 



F labellmn, Gardiner, Marine Investigations in South Africa, 

 Vol. II., p. 117 (1902). 



I have already reported on the specimens of this genus, but 

 two corallites which I at first referred to Desinophylluni, evi- 

 dently belong to it as well. The essential difference between 

 the two genera lies in the fact that the wall of the calicle is 

 formed by epitheca in Flahelhini, but by theca in Desmo- 

 ■phyllum. Delicate wavy transverse growth-lines are character- 

 istic of Flabellum, and belong to the epithecal corallum. A 

 true columella is present in neither genus, but either may have 

 the axial fossa filled in by the fusion of the septal edges or by 

 trabeculae from the same. 



