154 TIIREE CRUISES OF TIIE “BLAKE.” 
bean. The specimens of Fungia symmetrica, and Diaseris 
erispa (Fig. 477), if found in a sea where 
larger Fungi were common, would natu- 
‘ally be considered as the young of one of 
them. 
Antillia explanata (Fig. 478) is the 
first species of this tertiary genus found 
Fig. 478. — Antillia ex. living. 
planata. {. (Pourtalès.) Attached to the test of an Asthenosoma, 
from a depth of 373 fathoms near Montser- 
rat, came up a fine specimen of the delicate Leptonemus dis- 
cus (Fig. 479), in which the corallum is reduced to a mere lace- 
work. 
Fig. 479. — Leptonemus discus. S. (Challenger.) 
Among corals recalling extinct types are specially to be men- 
tioned Haplophyllia (Fig. 480), Dun ‘ania, and 
Guynia, which were surmised by Pourtalés to be- 
long to the Rugosa, an order established by Milne- 
Edwards and Haime for a large number of fossil 
corals, abundant in palieozoic times. Their chief 
Fig. ia characteristic is the development of the septa from 
Haplophylin four primary ones (Fig. 481), whilst in all of the 
M Mn Lrodiviagenei the "mary number is six. In addi- 
(Pourtalès.) o l bj i 
tion, the chambers are closed by floors. Ludwig 
has shown, however, that this tetrameral arrangement of the 
