w 
196 
Fungia fragilis (Alcock). 
(PI. V, figs. 18 and 19). 
Fungia fragilis Boschma 1923 c. 
Localities ^): Cycloseris-spec'imQns: 
D. Exp. t. Kei I si.: (Stat 39, 60 m, 3 ex.) 
Dr. Mortensen’s Pacific Exp.: Jolo, Sulu Islands, ca. 45 m, 16 ex. 
Dmsms-specimens: 
D. Exp. t. Kei I si.: (Stat. 10, 50 m, 1 frgm.; Stat. 53, 85 m, 2 frgm.; 
Banda, various localities, 25 — 100 m, 50 frgm.; off Samalona, near Macasser, 
15—20 m, 2 frgm.) 
Dr. M o r t e n s e n’s Pacific Exp.: Jolo, Sulu Islands, ca. 21 m, 2 ex. 
Some of the Cycloseris-specimens of F. fiagilis show a super- 
ficial likeness with the figure of Cycloseris mycoides Alcock, but 
this latter species has a loosely reticulate columella, whilst the 
columella in F. fragilis consists of a great number of small rounded 
isolated papillae. 
A number of specimens are much thicker than others, their 
septa are stronger and possess somewhat larger dentations which 
are also more regularly arranged than those of the more delicate 
specimens. In some of these thicker specimens there is also a 
slight difference in height between the marginal part and the central 
part of the septa of the lower cycles: these diminish in height 
where they unite with two septa of a next higher cycle. In the 
central part of such a corallum the septa of the lower cycles are 
easily to be distinguished by their greater prominence. The structure 
and arrangement of the septal dentations and granules and of the 
costal spines is quite the same as in specimens in which the septa 
are all of equal height, and therefore this prominence of the chief 
septa is only due to the stronger development of the corallum as 
a whole. 
In many specimens the upper surface is strongly convex, the 
lower surface concave. This is the case in all the larger specimens 
from Jolo, which therefore possess a very peculiar form (figs. 18 
and 19). Some measurements in mm of specimens from Jolo are 
given in the following table. 
Among the material of the Siboga Expedition there are two 
specimens from Stat. 315 (Paternoster-Islands) which are almost 
9 cf. foot-note on p. 192. 
