274. PERCY SLADEN TRUST EXPEDITION. 
The costal spines with growth of the coralla increase greatly in thickness and become 
relatively blunter and more granular; the actual number in the central area remains 
about the same, but they present a much more crowded appearance. Increase pro- 
portionate to age may be seen in the size of the imperforate area, in the thickness of the 
coralla and of the septa, in the sizes of the septal teeth (which, however, always remain 
very small) and of the tentacular lobes of the septa, and in the number of the septa. In 
the younger specimens ridges may be clearly distinguished running on to the septa from 
their teeth at right angles to their edges; as the coralla increase in size they become 
less distinct. In small specimens the septa of cycle V (the second 48 septa) may show 
indications of tentacular lobes, but they are subsequently obliterated by growth. 
Localities. Salomon Atoll (8), Egmont Atoll (5), Peros Banhos (1), all Chagos Archi- 
pelago: and Zanzibar (1) and reef off Sawakin, Red Sea (1 broken), both collected by 
Mr. C. Crossland. 
The species is of general distribution on coral-reefs situated in the tropical waters of 
the Indo-Pacific Ocean. The only record of the species from the Seychelles region of 
the Indian Ocean, where we searched particularly for it, is from Aldabra (Déderlein, 
loc. cit. p. 96). 
e. Hehinata-group. 
9. Fungia echinata (Pallas). 
Déderlein, Senckenb. naturfors. Gesellsch. Abhandl. xxvii. p. 101, t. 10. figs. 1-5. 
I have a large specimen before me from Talisse Island, N. Celebes, collected by 
Prof. S. J. Hickson. I have also examined ten specimens in the British Museum, all of 
fairly large size. All are rounded at their ends, and in no case does the axial fossa show 
any indication of having extended out to the end of the corallum, a striking contrast to 
F. simplex below. It is common for pairs of septa of opposite sides of the corallum to 
fuse across the axial fossa. 
This species is found from the Red Sea to Tahiti and Hawaii. 
10. Fungia simplex, Gardiner. 
Herpolitha simplex, Gardiner, Fauna and Geogr. Maldives & Laccadives, p. 943, pl. 91. fig. 13. 
This species was founded on a single fine specimen, dredged in the Maldives from 
25 fms. It differs from all other Fungia in having the axial fossa extending right out 
to either end of its elongated corallum. This is a character found otherwise only in 
young Herpolitha. It may be a young form of some species of that genus, but, if so, 
Herpolitha must have had a double origin, 7. e. from the Lcehinata- and the Scutaria- 
groups, as it is quite clearly related to the former subdivision. Again, it might be a 
young F. echinata, but its fossa is quite different from that shown in the youngest 
specimens figured by Déderlein, 
I was incorrect in stating that the specimen has no scar; further cleaning shows that 
it has a distinct trace of a scar about 6 mm. in diameter. 
