﻿1.80 MADEEPOEAEIA. 



The existence of these peculiar growth-forms strengthens my conviction, based originally 

 upon the great plasticity of the coenenchyma (see Introduction, p. 2), that this genus wiU one 

 day prove to be one of the richest in species of all the stony corals. In the meantime, however, 

 we want rather series showing the history of the different stocks and their possible variations, 

 than new isolated specimens. 



The coral, of a brilliant green colour, is from Sandal Bay, Lifu. 



a. Sandal Bay, Lifu. CoU. WiUey. (Type.) 



139. Montipora saxea. 



Description. — Corallum encrusting or massive, with nearly even, rounded, slightly pitted 

 surface. 



Calicles minute, • 5 mm., very numerous and evenly distributed, and in two forms, (a) In 

 the thinner encrusting specimens, the margin is clear and round, sharply circumscribed, with 

 two cycles of very minute septa, just distinguishable into primaries and secondaries, but with 

 two very conspicuous directives which stand up conspicuous to the naked eye as exsert plates, 

 knobs or spines, very irregular in shape and reaching to about the half radius circle. (&) In 

 massive growths, the calicles are not sharply defined, and only the primaries rise to the surface, 

 the secondaries appearing only below the margin. The two large directives are just as 

 irregular but are not so conspicuous. 



The coenenchyma very soon (5 mm. below the surface) becomes quite solid and stony ; 

 from this the threads of the reticulum rise up as thin, densely packed, harcUy distinguishable 

 trabeculse. At the surface the coenenchyma surges up, but quite irregularly, rising up into 

 small pimples but without any definite association with the calicles, sometimes lifting them, 

 sometimes tilting them, sometimes merely raising the interstitial spaces. The surface textures 

 consist of the loose ends of the reticular threads pointing in all directions ; in encrusting 

 specimens it is dense, but in the massive specimens it is open, the threads branching above the 

 surface. 



There are two specimens of this coral, which is distinct from any hitherto described. One 

 is an encrusting form about 1 cm. thick, the free edges of which have been unfortunately 

 broken away, and the other is a fragment chipped out of a massive block. Close examination 

 shows that the former of these must have flaked off from a massive block over which it 

 was apparently creeping. Both are much perforated by boring bivalves, which apparently 

 live with the coral, keeping their siphons above its surface. The encrusting specimen is 

 full of small calcareous worm-tubes which open near the calicles flush with the surface. 

 (Cf Astrceopora gracilis, vol. ii. p. 93). In life, the colour varies from purple to violet. 



In the irregular character of the papillas this coral reminds one of M. guppyi, while in 

 the size of the calicles and in the two conspicuous exsert septa it resembles the purely 

 glabrous species M. exserta. The name was suggested by the sudden solidification of the 

 coenenchyma 5 mm. below the surface, so that it builds up masses of solid rock, in which may 

 be incorporated other corals which happen to come in the way of its growth. The corroded 

 remains of a Podllopora are seen in the larger of the t^'o type fragments. 



a, I. Funafuti, EUice Islands. Coll. Gardiner. (Types.) 



