﻿FOVEOLATE MONTIPOK^. 59 



/. Young encrusting colony. Prof. A. C. Haddon. 



g. Warrior Island. Coll. SaviUe-Kent. 92. 12. 1. 340. 



h. Eocky Island. CoU. SaviUe-Kent. 92. 12. 1. 260. 



i. Kandavu. H.M.S. ' ChaUenger.' 



j. New Guinea. Vienna Museum. 97. 6. 18. 30. 



? k. Macclesfield Bank, 15 fathoms. Coll. Bassett-Smith. 93. 9. 1. 86. 



Var. piriformis. 



In addition to the above is a specimen which deserves describing by itself. It is a 

 pear-shaped mass, attached by a comparatively thin stalk of corroded coral (genus unre- 

 cognisable). The top is broad and flat, and the whole must have been very top-heavy; 

 the calicles are smaller than in the type, but have the twelve regular septa, and the light 

 reticulum swells up irregularly so as to form groups of false calicles ; the process, however, is 

 so uniform that the whole mass retains its general symmetry. (See further Appendix.) 



I. Shortland Island, Solomon Islands. Dr. Guppy. 84. 11. 21. 38. 



42. Montipora calcarea. (PI. X. ; PL XXXII. fig. 13.) 



Description. — Corallum a flat expanse with slightly turned-up edges, growing horizontally 

 across the edges of previous growths, and over the tips of branched corals. A number of 

 thin, digitiform processes (5 to ,6 cm. high) rise from its surface, some singly, others fused 

 into groups; a certain number of these are encrusting worm-tubes of various sizes. The 

 epitheca in patches follows the growing edge, even curling tup on to it. The living corallum 

 protrudes through the epitheca in patches, probably for fresh points of attachment. 



Calicles numerous, crowded, slightly sunk, as a rule less than their diameter apart, about 

 • 75 mm., conspicuous, deep, with very open fossa. Parts of two cycles of septa feebly and 

 irregularly developed near the apertures, but in the shallower calicles, i.e. on the thianer 

 parts of the corallum, either all or else the two directive septa fuse with a central irregular 

 rod-like columella. On the under surface, the calicles are surrounded by continuous solid 

 rings with slight points indicating the septa ; here and there the rings trace out accurately 

 the star-like shape of the aperture. 



The ccenenchyma shows in section a typical streaming layer which is a rather loose open- 

 meshed reticulum composed of stout threads and bands. This gives rise, both ventrally and 

 dorsally, to much denser layers ; the ventral layer, when resting on an epitheca, may become 

 quite solid ; elsewhere it is well developed and almost as thick as the upper layer. The 

 surface of the ccenenchyma, in. hollows and where growing rapidly, is a smooth reticulum ; 

 elsewhere the interstices are aU slightly swollen and rendered noticeable by the presence of 

 a thin knife-like ridge (sometimes double) rising up half-way between the calicles. These 

 thin ridges which, when seen under a pocket lens, are very porous and irregular, may join 

 together to form continuous irregular hexagonal patterns over patches of the surface. In their 



I 2 



