﻿TUBEECULATE MONTIPOE^. 123 



chief peculiarity. Tall, irregular tubercles rise up in the proximal walls of the calicles at the 

 outer edges of their solid ring-like margins, but seldom surround the whole calicle. These 

 tend to raise the whole calicle a little above the surface. The interstitial tubercles are like 

 small, scattered, feathery grains rather far apart, and rising up from[a solid-looking layer of stout 

 flat flakes with large round pores. The interstices are thus in marked contrast to the irregular 

 eruptive calicles with their one or two tall tubercles. On the under surface the reticulum is 

 so open that the meshes are very conspicuous. 



There is only one fragmentary specimen of this type. It is a new growth started at the 

 edge of a former dead frond. It is 6 cm. deep and 11 wide, and the dead growth to which 

 it is attached is about the same size and shows essentially the same method of growth. I 

 have been unable to associate it with any other specimens in the collection. Like the last 

 two species its tubercles are feathery and indistinct. 



a. Tongatabu. J. J. Lister, Esq. (Type.) 



101. Montipora grisea. 



Description. — CoraUum thin, explanate, apparently forming flat lobate fronds broader 

 than they are long, 2 mm. at growing edge, 4 mm. at 6 cm. further in. Epitheca to within 

 1 cm. of margin. 



Calicles inconspicuous, except at growing edge and on young fronds, scattered, • 3 mm. 

 in diameter, star-like, with well developed primaries and traces of rudimentary secondaries. 

 On the under surface the calicles are hardly visible to the naked eye, excessively minute, 

 very irregular in shape, and with parts of two cycles of septa. 



Coenenchyma a very thick, open, filamentous streaming layer, forming on the surface of the 

 margin numerous feathery processes which point outwards and generally rise as the proximal 

 walls of sloping calicles ; as the coenenchyma thickens these processes are immersed, and the 

 surface is purely reticular. In this reticulum short stout trabeculae appear, showing every 

 stage of their development as submerged tubercles. These latter are smaE rounded bushes, 

 so loose and feathery as to have no sharp outline to the naked eye. They are very irregularly 

 distributed in uneven groups, tending to be taller the further away they are from the growing 

 edge, towards which they all slope excepting on the oldest central portions of the stock. They 

 rise within the interstices and seldom from the immediate walls of the calicles, the apertures 

 of which are distinct. The imder surface is purely reticular, the threads being close and thick. 



The specimens on which this type is founded are three small fragments, two of which 

 appear to be regular lobate fronds, broader than they are deep, and in both cases the posterior 

 lateral lobes of the broadening frond form folds with the flat stalk of attachment. The basal 

 parts of the fronds are corroded. The depth of the living zone is only 5 cm. The section of 

 the corroded portion of the old stock shows the same thick spongy streaming layer above 

 described ; here and there it has deposited a solid layer on the epitheca, and the trabeculae are 



K 2 



