﻿182 MADREPORARIA. 



tubercles; actual aperture 0*75 mm., the diameter of the ring of tubercles 1"5 mm. Irre- 

 gularly distributed but generally less than one diameter apart. Each ring of tubercles being 

 in contact with another ring. Twelve nearly equal symmetrical septa, which are short and 

 thick, but wedge-shaped seen from above. Two more massive directives often interruptedly 

 laminate. Tubercles rise straight above the peripheral ends of septa, there being no proper 

 margin to the calicle aperture. Fossa open and deep. Well formed calicles seen right round 

 the face of the growing edge up to the border of the epitheca. 



Ccenenchyma shows in section a thick, solid layer resting on the epitheca and extending 

 almost to the growing edge ; the streaming layer is thus very early obscured, the actual edge 

 itself being apparently formed of outwardly curving trabeculse, projecting from the solid layer. 

 This latter varies from 1 to 1 • 5 mm. thick, and upon it rest the densely packed trabeculse 

 which are stout, • 5 mm. thick, but taper somewhat near the surface, so that the tubercles 

 arising from them are small, 0*25 to 0*3 mm. in diameter. The tubercles are arranged 

 in low regular rings round the calicles, remaining distinct, round, frosted or bushy, and 

 from 8 to 9 in each ring. They rise less than 0'5 mm. above the surface, but are con- 

 spicuous owing to their whitish frosting. The interstitial spaces are smooth and slightly 

 concave, their floors, however, are composed of the rounded tops of closely packed but distinct 

 tubercles. One or two may occasionally rise, but do not reach to the level of the top of the 



This description is based upon what appears to be the normal portion of a specimen, 

 part of which is reflexed and consequently greatly distorted. The conspicuous ringed 

 calicles, with smooth concave interstitial spaces, are peculiar features. The whole of these 

 characters, however, are lost on a portion of the fragment which is folded round xmder two 

 thick layers so as to form a nodule. The tubercles here all rise up thickened, fused into plates 

 and crowded together, so that the calicles, which are also very crowded, are sunk deeply 

 down below the surface formed by tlie tops of the tubercles. 



This specimen, though only a fragment, is separately described on account of the peculiar 

 arrangement of the tubercles. It is possible that if the complete stock were known it might 

 be allied with one of the existing species. The uniformity in shape and size of the tubercles 

 surrounding the calicles places it near the lequi-tuberculate group, M. peltiformis, M. granulata, 

 and M. cequi-tuberculata. 



a. Sandal Bay, Lifu, Loyalty Islands. Coll. Willey. (Type.) 



141. Mcntipora granifera. 



Description. — Corallum, complete form unknown, encrusting, 5 mm. thick. 



Calicles crowded, conspicuous, sunk among the forest of tubercles. Two cycles of septa, 

 thin, symmetrical, primaries twice as long as secondaries, two directives reach to the half 

 radius circle. The tubercles rise straight over the peripheral ends of the septa, there being no 

 proper margin to the calicle. Fossa open and deep. 



