﻿APPENDIX TO THE GENUS MONTIPOEA. 17& 



It becomes more and more clear to me that the simple surging Tip of the interstitial 

 ccenenchyma above the level of the calicles, so as to form protecting ramparts round the 

 polyps, i.e. foveolation, has been a very successful specialisation. It has certainly been 

 developed in a great number of Montipores, but with shades of difference which effectually 

 baffle the systematist. The attempt here made to group the specimens which show this 

 character into species and varieties must be regarded as purely provisional, untU longer and 

 more complete series are at hand. 



i. Papillate. 

 138. Montipora alveopora. 



Description. — Corallum is tall and roughly conical, the cone standing on its apex, and 

 built up by tiers of smaller solid cones, each tier starting from the platform made by the fused 

 tops of those forming the underlying tier. While some of the spaces between the individual 

 cones persist in the heart of the stock, all traces of the separate cones are obliterated externally, 

 except on the uppermost platform where the new tier is forming. Here the cones which rise 

 up and fuse to form the next platform are seen to spring up from among a great number of 

 irregular digitiform processes. 



Calicles on the sides small, • 5 mm., uniform, inconspicuous, evenly distributed about 

 1 mm. apart, margin generally sharply circumscribed but irregular in shape, and with part of 

 two cycles of short septa, the primaries only just distinguishable from the secondaries. On 

 the flat tops of the rising cones the calicles are crowded in valleys between the surging papillse, 

 and are then separated merely by their angular membranous walls, with a few irregular septal 

 spines. They strongly resemble the calicles of the genus Alveopora. 



The ccenenchyma consists of a friable, delicate and very porous laminate streaming layer 

 which carries the coral upwards. This forms the floors of the platforms, and, by bending out- 

 wards horizontally with very little change, the sides of the cones and of the other rising 

 processes. On the sides of the cones, and especially near the tapering tips of the digitiform 

 processes, the ccenenchyma rises up to form very irregular underlips, which are without any 

 sharp outlines, and are mere confused projections generally associated with the lower margins 

 of calicles. The surface is either formed of an open reticulum formed by the jagged ends of the 

 streaming layer, or as on the sides of the coral, a system of flakes formed secondarily parallel 

 to the surface. This gives the sides a rather solid appearance and surrounds the caUcles with 

 continuous solid-looking rims. The lower portions of the coral do not appear to solidify ; 

 numerous fragmentary horizontal membranes, " tabulae," appear periodically, marking the with- 

 drawal of the living tissue from the lower parts of the skeleton. 



The type specimen is part of a stock, the rest being in the Cambridge University Museum. 

 It stands 18 cm. high, and shows traces of three successive tiers of inverted cones each about 

 6 cm. high. The coral had been broken from its base, the place of fracture being some 4 to 

 5 cm. across. Thus it is possible that one more tier consisting of but one or two cones hadi 

 preceded those which composed the specimen. 



2 A 2 



