54 THE VOYAGE OF H.M.8. CHALLENGER. 
on the apical parts of the branches and branchlets a small style is visible at the junction 
of the septa, no indication of it is present in the other calicles of the corallum, where the 
columella takes the form of a thick central concave mass with which the septa are 
united. 
1. Stylophora digitata (Pallas). 
Madrepora digitata, Pallas, Elench. Zooph., p. 326. 
Pocillopora andreossyt, Savigny, Egypte, Polyp., pl. iv. fig. 3. 
Stylophora digitata, Milne-Edwards and Haime, Cor., ii. p. 135. 
Two specimens were collected which, though presenting interesting varietal differ- 
ences, can be separated from this species by no constant characters. In the one, which 
is large and thick, many of the branches are divaricate or subdivaricate, very swollen and 
obtusely rounded at the apex; the calicles are quite large and rather far apart, and the 
labial projections small, more especially at the apical parts. In the other, which is of 
much smaller growth, the branches are much subdivided and ascending, becoming quite 
small and subacute above, and the calicles are rather smaller and closer and less promi- 
nent at the upper margin. 
A very good description, with figures, is given by Klunzinger in his work on the Red 
Sea Corals. 
Localities. —TVhe larger specimen from Somerset, Cape York, 5 fathoms; the smaller 
from Amboina. 
2. Stylophora flabellata, n. sp. (Pl. I. figs. 1-10). 
Corallum flabellate; the branches subequal, rapidly dichotomising at a rounded 
angle and always regularly in the same plane, very unevenly bent, compressed so as to 
present an elliptic outlime in transverse section, which is uniformly about 8 to 10 mm. 
in diameter in the long axis, though somewhat less at the base; branchlets slightly 
smaller than the branches, quite short, subterete, very obtusely rounded. — Calicles 
circular or subcircular, rather deep and large, 1 to 1°5 mm. in diameter, very elongately 
spinulous at the margin, not touching but often separated from each other by wide 
interspaces, nearly even with the surface, and not prominent at the upper margin. Septa 
six, extremely narrow above, where they are seen as slightly thickened prominent 
spinules at the margin of the calicle, distinct only at the basal part of the fossa, where 
they thicken and unite at the centre to form a thick central columella which is produced 
upwards as a small style, and which is generally slightly elongated in the direction of the 
long axis of the branch. The interseptal chambers are usually very deep, especially those 
which are situated at the distal part of each calicle; they are generally narrow, but 
