﻿PAPILLATE MONTIPOR^. 93 



latter are of all sizes, so that it is often not easy to say whetlier a given excrescence is a 

 tubercle or a papilla. 



The streaming layer forms the greater part of the section. A solid layer is deposited 

 upon the epitheca, but the typical knob-Kke protrusions of the reticulum break through this 

 solid layer. The epitheca grows over them, but one or two calicles may remain open on their 

 most distal surfaces. The tubercles seem to have hardly any trabecular roots, as above the 

 streaming layer the reticulum is very thin. Hence the difficulty of ascertaining whether a 

 given excrescence is a tubercle, that is, a thickening of a single thread of the reticulum, or 

 a papillate upheaval of a mass of the reticulum itself. The calicles are hardly visible except 

 ■with a lens, being hidden among the low tubercles. The specimen was labelled M. lima and 

 tied up with specimen d. The specimens of M. minuta with which it appears to be allied 

 were also labelled 3£. lima. 



h. Macclesfield Bank, China Seas, H.M.S. ' Eambler.' 



20 fathoms. 



72. Montipora prolifera. (PI. XVIII.) 



Montipora prolifera, Briigg., Journ. Mus. Godeffroy, xiv. (1879) p. 209. 

 Montipora lima, Id. ibid, (non Lamarck). 



Non Montipora prolifica (= prolifera), Bassett-Smith, Ann. and Mag. Nat. Hist., vi. (1890) p. 450 

 (see M. pulcherrima). 



Description. — Corallum consists of large (usually distorted) fronds which bend upwards as 

 they freely expand. The more horizontal fronds have the epitheca stretching almost to the 

 growing margin. On the more sloping fronds the epitheca is from 3 to 4 cm. distant from the 

 margin. Edge 2 mm. thick in the more sloping fronds. In older stocks the corallum is 

 thickened by successive encrustations over the surface of the more horizontal fronds. 



The calicles are star-like and very numerous, here and there being less than their 

 diameter apart, often arranged conspicuously in radial rows between the ridges. They vary 

 in size according to the thickness of the surrounding ccenenchyma. On young fronds they 

 are inconspicuous and between • 3 and • 25 mm. in diameter ; in older and thicker portions of 

 the same stock they are ■ 5 mm. Twelve well developed septa, the secondaries being slightly 

 smaller than the primaries. The fossa is open and deep. On the under surface the calicles 

 are very unevenly distributed ; a few excessively minute apertures are found near the margin 

 opening on the level surface of the dense ccenenchyma, while further away others, larger, 

 ■ 25 to • 3 mm., open on papillffi. 



The ccenenchyma shows in section the streaming reticulum on the one hand, depositing a 

 thick dense layer on the epitheca, while on the other it rises up into the papHlse and ridges of 

 the upper surface. The surface shows great variations, according to the slope and age of the 

 frond. In young fronds and larger upwardly sloping first growths the papillae (which may 

 be quite small and indistinguishable from tubercles), fuse to form ridges, which may or 

 may not run together to form long radial keels. Such ridges, when formed, may be regularly 



