436 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 6, 



18. Cyphastr^ea costa ta, spec. nov. 



This species is found also at Barbuda and Jamaica (see Barbuda, 

 page 443). 



Prom the Mvaje shale. Coll. Geol. Soc. 



19 a. Stylophora affinis, spec. nov. PI. XYI. fig. 4. 



Corallum branched, large; branches nearly cylindrical, leaving 

 the stem at an acute angle, slightly flattened on one side. The 

 largest stem is |- inch in diameter. Blunt, aborted, branch-like 

 swellings exist on some of the larger stems. Corallites radiating 

 from the centre of the stem and branches, separated by about their 

 own width of dense ccenenchyma, which is seen, in the larger speci- 

 mens, to be very slightly cellular. Walls not distinguishable from 

 the ccenenchyma in the substance of the mass, but slightly raised 

 into a very shallow crateriform edge on the surface. Calices cir- 

 cular, a very little raised as crateriform elevations, very numerous, 

 disposed irregularly, but very nearly equidistant in some places and 

 less so in others ; margins sharp. Diameter -^ inch, rarely larger. 

 The calicular margin, when well preserved, looks like a little ring 

 placed on the intercalicular space, and the small styliform columella 

 renders the appearance very distinct. Intercalicular spaces marked 

 by "a continuous and ridged line, which, being in the part of the 

 spaces at the base of the calicular elevations, and being continued 

 round each calice, is, from its general straightness, formed into irre- 

 gular polygons. The line is sensibly raised, convex, and now and 

 then dentated. Between the line and the calicular margin there are 

 distinct papillae, one row at the very marginal edge, the other corre- 

 sponding to it a little lower down the calicular wall ; a third is some- 

 times seen ; and in places where there is an unusual distance between 

 the calices, and when the " line " is wanting, the papillae are nu- 

 merous, distinct, and a little smaller. The line and the papillae form 

 a very marked distinction. Between some calices there are faint 

 elevations. Septa whole, not exsert, but little visible in perfect 

 calices, but very distinct when the coral is worn. Upper margin 

 perfect, and concave upwards, the septa appearing festooned to the 

 columella; they are delicate, very little thicker at the wall than 

 elsewhere, and join the columella high up near its point. The papillae 

 at the calicular edge extend a little on the wall, and may be con- 

 sidered as rudimentary septa and costae ; if so, there is a second 

 cycle, and also a third in half of each system. The persistence of 

 six septa, nearly all of the same size, is very remarkable. Columella 

 styliform, large and dense in the corallite, and forming a rounded-off 

 cylinder with a sharpish rounded tip, which is very distinct halfway 

 down the calice. Calicular fossa shallow, about half as deep as broad. 

 Endothecal dissepiments stout, transverse, numerous. The walls and 

 columella do not fill up the lower parts of the corallites. Increase 

 by extracalicular gemmation. 



From the Nivaje shale Coll. Geol. Soc. 



19 b. Var. minor. 



A portion of a branched Stylophora in a mass of shell- and coral- 



