﻿52 MADREPOEAEIA. 



developed and while it is being developed, the interstices rise up into ridges between the 

 caLicles, giving the surfaces of these parts a very pitted appearance ; this, however, passes away 

 as the stem thickens. 



This coral from the Solomon Islands resembles M. fruticosa in the aspect of the calicles, 

 looking, with their aborted septa, as clear round punctures in the smooth solid stem ; but it 

 differs from it in the size of the calicles and in the foveolate character of the surfaces of the 

 branches. In this latter respect it comes near Montii)ora gaimardi, where the foveolation may 

 be very pronounced ; but in the almost complete absence of septa it differs greatly from this 

 type in wliich the primary septa are very highly developed and conspicuous. It is also 

 altogether more delicate and smaller than M. (jainiardi. 



In these points also it differs from Dr. Guppy's specimens of M. digitata from Shortland 

 Island, Solomon Islands, although it somewhat resembles them in the character of the coenen- 

 chyma in cross section. 



a. Solomon Islands. Vienna Museum. [97. 6. 18. 17.] (Type.) 



Group III.— FOVEOLATE. 

 a. Sncrnsting and Hising into Lobes. 



37. Montipora libera. (PL VI. fig. 3 ; PL XXXII. fig. 6.) 



Bcscri2Jtion. — Corallum consists of a flat unattached mass of rounded nodules, the whole 

 built up by successive incrustations of a thin layer of coral, from 2 to 3 mm. thick. Each 

 incrustation grows round and rmder the mass, the whole gradually losing its rounded symmetry 

 by enclosing foreign objects which have become attached to the stock. 



Calicles crowded and conspicuous, but sunk beneath interstitial ramparts, from 1 mm. in 

 diameter on the smooth rounded upper surfaces of the nodules to minute specks crowded 

 together in the shallow valleys between the same. The aperture is generally a well marked 

 membranous ring, with twelve short and nearly equal septa, or else with two distinct cycles, 

 the primaries being twice as long as the secondaries. Of' the two directives, one may be 

 strikingly exsert, rising almost as high as the interstitial rampart. The directives are 

 frequently continuous laminfe. 



Cojnenchyma consists of a Light echinulate reticulum, which rises in narrow ridges 

 forming angular ramparts round the calicles ; young calicles often open at the angles where 

 the ridges meet. The ramparts are in marked contrast to the membranous rings sunk down 

 in their bases and which outLiae the caLicle aperture. "VVlien these membranous rings rise 

 up in the bases of the ramparts the calicles appear to have double walls. 



