INDIAN OCEAN PORITES. 199 
No two calicles could be more unlike than those on the top of this hard, dense mass and 
those on the soft-looking, rounded stock presented by No. 1. And yet here the same soft, 
woolly look and the same ealicles as those of No. 1 appear on the basal rim of this column. 
a, *Zool. Dept. 1904. 10. 17, 44, 
199, Porites Ceylon (298, (P. Ceylonica tertia.) (Pl. XXX. fig. 4.) 
[Ramesvaram, coll. E. Thurston; British Museum.] 
Description.—The corallum has the same widely outspread unattached base, under the 
middle of which are the tdecayed remains of earlier stocks. Above this base, with its slightly 
projecting rim, the mass rises into a narrowing column of erect processes of all sizes, from 
minute knobs and points to tall, stout, flattened ridges, blunt points, or angular knobs, 
some of which are as much as 15 em. high, 7-8 em. across, and 3-4 em. thick. 
The calicles over the greater part of the stock are like those halfway down the sides of 
No. 2. They are larger and rounder than the topmost calicles of that specimen, but again 
gradually change round the base into those characteristic of No. 1, Here and there the 
walls return to being single threads, At the tops of the processes the calicles open irregularly, 
a streaming reticular layer, loose, open, and flaky-filamentous, The sections show remarkable 
differences of density. Where the calicles are smallest and most like those of No. 2, the 
trabeculee are closely packed, but where the calicles are like those of No. 1, they are separated 
by rows of much larger pores, » 
This specimen is of peculiar interest, because it seems possible to trace a distinct correlation 
between the type of the calicle and the forms of the rising processes. Where the calicles are 
like those of No. 1, or approach that type, the processes are rounded, thick, and softer looking. 
Where they are like those of No. 2, the processes tend to narrow into hard ridges, 
It is worth pointing out that the corroded remains of previous growths found embedded 
under the base of this great specimen still show quite clearly, both in shape and texture, that 
they were at one time like No. 1. 
a, Zool. Dept. 1904. 10. 17, 45. 
200, Porites Ceylon (294, (P. Ceylonica quarta.) (Pl. XXX. tig. 5; Pl. XXXV. fig. 31.) 
| Ramesvaram, coll. E. Thurston ; British Museum. ] 
Description.—The corallum expands with a wide, thick, cushion-like edge, deeply incised 
and pendent, freely above a loose cluster of small rounded stocks of apparently the same 
