﻿PAPILLATE MONTIPOE^. 107 



There is only one specimen of this coral. It is a fragment 7 cm. deep by 13 cm. long, 

 broken from the edge of some larger explanate growth. It is quite unique in the collection, 

 and ought perhaps to be classed separately on account of the small sizes of the papillae, the 

 exsert directives and the general texture of the coenenchyma. 



a. Thursday Island, Great Barrier Eeef. Coll. Saville-Kent. 92. 12. 1. 287. 



Montipora verrucosa, variety 7. 



A massive specimen, • 5 cm. at the creeping edge, 3 cm. thick in the centre ; encrusting 

 dead coral. The papillse are typical but smaller, 1*5 mm. higli, 1 mm. thick, and more 

 scattered. The small calicles are densely crowded, less than one diameter apart except when 

 papillse fill up the interstitial spaces. The septa well developed; two cycles of septa. 

 Two primaries (directives), sometimes three, very thick and prominent, being visible to the 

 naked eye as short white lines reaching almost to the centre of the calicle, sometimes as very 

 exsert plates. 



As in the case of the last specimen, I was inclined to class this also separately. But the 

 coenenchymatous specialisation being essentially the same as in M. verrucosa, I prefer to class 

 it as a variety rather than multiply species based on single specimens. 



a. Great Barrier Eeef. Coll. Saville-Kent. 92. 12. 1. 543. 



8L Montipora ambigua. (PL XXL fig. 1 ; PI. XXXIII. fig. 12.) 



Descrijotion. — Corallum explanate, edges slightly raised, ■ 5 cm. thick at edge, 1 cm. in 

 older portions, and still further thickened to 2 cm. by the irregular extrusion of calicle-bearing 

 coenenchyma through the dead under surface. A feebly developed epitheca apparently 

 curled over and forced back by a layer of coenenchyma growing backwards from the edge. 



Calicles are conspicuous as black dots 0'5 mm. in diameter, aperture sunk in slight 

 depressions of the surface reticulum. Two cycles of short thick septa irregularly developed. 

 Where the corallum is thickening very rapidly, even submerging the papillse, the apertures 

 may be surrounded by distinct continuous ccEnenchymatous rings. Elsewhere the interseptal 

 locuH are not distinguishable from the irregular meshes ■ of the reticulum. On the under 

 surface the calicles are of all sizes, from specks invisible to the naked eye to round open 

 calicles 0*75 mm. in diameter. The larger calicles are generally surrounded by a close 

 ring of dots, which stand slightly above the surface and appear distinct from the surrounding 

 reticulum. 



Coenenchyma in section shows a laminate streaming layer of u-regular thickness, and well 

 developed layers bending both upwards and downwards. The vertical elements of both these 

 form almost typical trabeculse. The reticulum of the upper layer rises into tall, round-topped, 

 generally cylindrical papillse, which rise sharply out of the surface reticulum and differ from 

 it in texture, appearing smooth and woolly, or echinulate under the pocket-lens. This differ- 



p 2 



