REPORT ON CORALS—EXPLANATION OF PLATES. 247 
by a series of transverse bars, between which lie more or less reniform 
depressions. The bottoms of these reniform depressions are traversed in their 
centres by the under edge of a septum, on either side of which is an oval 
perforation. 
Fig. '6. The same. Portion of the upper surface of the wall of the corallum near its 
margin to show the arrangements of the perforations. Two series of per- 
forations are shown. The perforations are disposed in pairs on either side of 
each septum, At the bottom of the figure the commencement of two septa 
are shown. ‘The wall is folded, so as to rise on either hand towards the lines 
of origin of the septa, thus forming a series of low ridge-like elevations, 
separated by corresponding lines of depression or valleys, the bottoms of which 
correspond with the costee. 
Fig. 7. The same. Diagrammatic representation of one of the septa seen from its side to 
show the arrangement on the septal margin of the paliform spines, and the 
indented lower border of septum. ‘The indentations correspond in position 
with the depressions seen in fig. 5. 
Fig. 8. Stephanophyllia formosissima. The coral with the soft parts zi situ to show the 
arrangement of the tentacles. On the right hand side the primary (1) and 
secondary (2) septa are indicated by lines to show the position of the tentacles 
with regard to them. Enlarged 2 diameters. 
Fig. 9. The same. Vertical section through the soft parts of a decalcified specimen. 
A, A. Apertures in the basal tissue, through which passed in the living 
state of the coral the transverse bars of the perforated wall of the 
corallum. 
B, B. Apertures in the mesenteries. 
C. Spongy mass of soft tissue covering the columella. 
D. Cisophagus. 
S. Stomach-cavity bounded by the edges of the mesenteries, each 
bearing meseuterial filaments. 
E. Principal or primary mesentery, showing the arrangement of mus- 
cular fibres upon it. 
OO Ova; 
Fig. 10. Diagrammatic representation of the mutual arrangement of the hard and soft 
parts in Flabellum, as seen in a section of a portion of it cut transversely 
to the vertical axis. The several layers are indicated by the shading 
throughout, the corallum being represented as black; E. Ectoderm; EN. 
Endoderm ; B. Mesoderm; W. Wall of the corallum; 8,8. Septa; M, M. 
Mesenteries ; A, A. Muscles of the mesenteries; MF. Mesenterial filaments ; 
T. A. tentacle. 
