488 J. W. Gregory & Jean B. Trench—Eocene Corals. 
The genus Coscinarea has always appeared out of place in the 
Agaricioida, in which Duncan placed it; and the characters which 
led to its reference to that alliance appear to be unessential features 
due to habit of growth. The characters of the septa show that 
Coscinarea is allied to the Jurassic genus Aobya. Owing to the 
kindness of Professor Stanley Gardiner we have been able to examine 
a series of specimens of Coscinarea, including some of the type 
species of the genus. Coscinarea appears to us to be a descendant 
of Kobya, in which the corallum, instead of being massive, is an 
encrusting lamina, and in which the corallites tend to occur in short 
series separated by raised bands that have sometimes the aspect of 
collines. The columella is small and deep. 
In Kobya the corallum is massive, the calices are separated by flat 
surfaces traversed by septocoste, the columella is large and, though 
parietal in structure, it may end above as a single papilla. The 
species of Kobya which most closely approaches Coscinarea is 
K. lenticulata (Gregory, 1900, p. 172, ‘pl. xxii, figs. 8, 4), in which 
the corallum is flat and lenticular. Tis corallites tend to grow in 
concentric series with slightly raised edges ; its corallum is, however, 
massive, and this species only indicates a tendency towards the 
characters of Coscinarea. That genus is one of the distinctive corals 
of the Indian Ocean and Red Sea, and the occurrence of Kobya in 
Bathonian and Eocene times in the same region is geographically 
consistent with the suggested relationship between the two genera. 
C. andrewst, the Miocene species from Christmas Island, was 
described as ‘‘apparently massive’’. It will therefore probably be 
found, when better specimens of it are available, to be a Hobya. It 
differs specifically from KX. hemicribriformis in that the corallites are 
much smaller; in the Christmas Island species the corallites are only 
10mm. and the columella 2mm. in diameter, whereas in KX. hemi- 
cribriformis they are respectively 15 and 3 mm. in diameter. 
EXPLANATION OF PLATES. 
PLATE XIX. 
1. Stylina macgregori, n.sp. No. 27. Fig. la, part of upper surface of 
, corallum, x 3 diam.; Fig. 16, part of polished surface of same 
specimen, horizontal section, x 3 diam. 
2. Leptoria carnei, n.sp. No. 6. Part of polished surface of corallum, 
x 3 diam. 
3. L. carnei,n.sp. No. 7. Part of polished surface of corallum, x 3 diam. 
PLATE XX. 
1. Plesiastrea horizontalis, n.sp. No.18. Fig. la, part of polished surface 
of corallum, vertical section, X 3 diam.; Fig. 1b, part of polished 
surface of same specimen, horizontal section, x 3 diam. 
2. Dachiardia macgregori, n.sp. No. 5. Fig. 2a, part of corallum showing 
a few corallites and granular surface, x 2 diam.; Fig. 26, part of 
polished surface of same specimen, X 2 diam. 
3. errors papuensis: n.sp. No. 22. Part of surface of corallum, 
% diam. 
(To be concluded in our next Number.) 
