﻿124 MADREPORAEIA. 



distinct and long. The type appears to be peculiar in the development of the coenenchyma. 

 These specimens, as well as the specimen of M. listeri, have the same blue-grey colour common 

 to the Turbinarians and Astrajoporans from this locality. 



a, I, c. Tongatabu. J. J. Lister, Esq. 91. 3. 6. 117. (Types.) 



a is the largest frond, 10 cm. broad ; & is a portion of a young frond which was about 

 6 cm. broad ; c is a bent, crumpled and corroded fragment of some old stock being re-grown 

 over by fresh coral. 



102. Montipora minuta. (PI. XXIII. fig. 3 ; PI. XXXIII. fig. 19.) 



Description. — Corallum minute, flat, or scallop-shaped growth of varying thickness, from 

 1 to 5 mm. Epitheca almost to growing edge, may, however, in thick specimens, leave from 

 1 to 2 cm. of under surface free. 



Calicles are conspicuous on thin specimens, being mostly raised above the surface by 

 irregular clusters of tubercles which are generally taller and more numerous on the side of the 

 calicle away from the growing edge. The aperture is abo\jt " 5 mm. across, with two cycles of 

 septa, generally regularly developed, the primaries reaching slightly beyond the half radius 

 circle. Where the under surface is not covered by epitheca it is covered with calicles, which 

 are open as very minute pores, and only seen to be star-like with a pocket-lens. 



The coenenchyma shows an open streaming reticxilum depositing a solid layer upon the 

 epitheca, and here and there in some specimens breaking through the latter to form knob-like 

 drops which are either entirely overgrown by epitheca, or still show an open calicle or two. 

 Towards the upper surface the streaming layer bends up to form a thicker or thinner layer, 

 according to the thickness of the stock. At the growing edges the streaming layer may rise as 

 radial papillate ridges, but the rest of the surface is tuberculate. The tubercles are of all 

 sizes, compact, cylindrical, with sharp outlines to the naked eye. They rise from trabeculae, 

 which also vary greatly in tliickness, some reaching nearly 1 mm. in diameter. The tubercles 

 tend to rise in irregular groups round the calicles, but do not form regular rings ; this is most 

 marked in the thinnest specimens, for in these the surface between the groups of tubercles may 

 be concavely simk. In thicker specimens tubercles may appear very irregularly all over 

 the surface even between the groups associated with the calicles. 



There are five specimens of this coral, which is closely linked with the specimens described 

 on p. 91 under the specific name M. pulcherrivia ; specimen g of this latter species is a 

 transition form, showing the gradual substitution of tubercles for radial ridges. These radial 

 ridges can still be traced in the specimens now under discussion. The alliance between these 

 two types is closely paralleled by that between many of the larger and more tropical foliate 

 Montipores. M. 'prolifera,, for instance, is entirely papillate. M. foliosa is partly papillate (with 

 papillate ridges) and partly tuberculate, while M. solanderi is almost entirely tuberculate. 

 So that if we accept Mr. Bassett-Smith's suggestion that some specimens of M, pulcherrima 



