MADREPORARIA. 767 



deep. Walls, either — over the greater part — rounded or slightly pointed above, not Tnore 

 than 1-5 mm. thick, with septa -5 ram. exsert, not generally extended horizontally, continuous 

 between calices, or — -a few places at the edges — 3 mm. or more thick with distinct furrow.^ 

 but theca never visible. Septa irregular, often 2 or 4 (presumably primaries) very much 

 thicker ("5 mm.) with exsert parts horizontally extended — evidently showing where division 

 is ultimately to take place — in the average calice about 21 in number, often the smaller 

 curving round to fuse with the larger, all thin with the exception of the large primaries, 

 granular on the sides, finely but very irregularly toothed, the lowest teeth of about 12 of the 

 largest rough, pointed and perpendicular, forming a more or less conspicuous pali-crown. 

 Columella always distinct, rather dense, commonly at least a quarter of the breadth of the 

 calice, formed by finely anastomosing trabeculae from at least one half of the septa. //( 

 section (which is not very clear) the exo- and endothecal parts appear rather vesicular, walls 

 compact. 



Locality. From the outer slope of the reef of Addu, 25/ The specimen (1.5 x 11 x 7 cm.) 

 is more or less incrusting and relatively thin. The species is nearest allied to the last, but 

 markedly differs from all known forms of the genus. 



22. Favia cavernosa (Forsk.). (PI. LXI. fig. 13.) Klz., p. 26, ill. 4. 



I refer to this species a rounded mass, 22 cm. in diameter, dead in centre but surroimded 

 by a belt 14 cm. broad, still living when obtained, and a second, dead in places, 15 cm. in 

 diameter by 13 cm. high. The second has rather thinner walls, higher calicular edges, 

 thicker costae and septae than the first. Both, especially the second, show recognisable, 

 paliform lobes in a few calices. The septa may be thickened or not, where they join the 

 theca. Traces of costae without corresponding septa are often present. Only in isolated 

 calices can the colunnella be termed " sehr wenig entwickelt," being generally nearly as well 

 marked and of the same nature as in F. denticulata. 



There appears to me to be little or no doubt as to the identity of these specimens with 

 Klunzinger's species, the figure of which is good. I accept the latter's synonymy, but I am 

 doubtful as to Favia okeni. 



Iiocality. Minikoi, larger from the flat behind the boulder zone, and smaller from a 

 lagoon shoal. 



23. Favia affinis Ed. and H. (PI. LXII. figs. 22 and 2.3.) . 



Ed. and H., ii. p. 429. Gard., p. 750. 



Three quite small specimens with ordinary calices (not undergoing fission) varying up 

 to 13 mm. long and 9'5 broad, and walls up to 3 mm. in thickness but averaging about half 

 this. The theca of the separate calices is not generally distinct, their exothecal connections 

 usually in the form of vesicles, convex above, and not mere dissepiments. The septa are 

 1 to 2 mm. exsert above the theca. The line of junction of the costae of neighbouring 

 corallites is shown by a very distinct notch or furrow, and in this position delicate, transverse 

 connections tend to form between them, where growth is vigorous. The edges of the septa 

 over the theca may be thickened, and are edged with fine teeth. They vary in number up 

 to 30, of which about half extend into the calice to form with fine, twisted trabeculae from 

 their edges a small columella, against which they end in relatively thick, blunt, often spined, 

 paliform teeth. 



