274 ATR. J. S. QARDrNBU OS THE PEEFOBATE [Apr. 5, 



Var. PAEViCELLATA. (Plate XXIV. fig. 1 1.) 



In this variety the calices are much smaller than in the type, 

 being seldom more than 1 mm. in diameter. The calices are 

 similar in appearance, but the septa are rather rougher, and the 

 pali more distinct from the septa and more prominent than in 

 either the type or the preceding variety. The columella, too, is 

 thicker and more prominent. 



Funafuti ; lagoon shoals. 



The species above described is subject to much variation in the 

 parts within its calices ; and in different parts of the corallum 

 nearly all the stages between the type and these tAvo varieties can 

 be found. For instance, the septa in some cells of the same colony 

 are quite thick with no distinguishable pali, while in others the 

 septa are thin and the pali well marked, perhaps completely 

 separate from the septa. In a curve of variation of these 

 characters there would seem to be two prominent points which 

 I have recognized in my descriptions of P. arenosa and its var. 

 lutea. It seems to me, too, that P. conglomerata (Bsper), 

 P. ixirvistellata (Quelch), and probably several of the "West-Indian 

 species, will have to be placed under this head, when a long series 

 is examined. 



The var. parvicellata differs mainly in the size of its calices, but 

 their great regularity precludes the idea of this being due to local 

 conditions. 



The living colonies, which are of a golden-green colour, are 

 common on all the shoals of the lagoon of Funafuti, but are not in 

 any way uncovered, even at the lowest tides. 



8. PoEiTES suPEEFirsA, n. sp. (Plate XXIV. figs. 1 m & 7.) 



CoraUum rough, closely incrusting, retaining the shape of the 

 surface over which it is growing ; the edges thin, 1-1 -5 mm., 

 closely followed underneath by the epitheca, often free for a few 

 mm. where the incrusted surface is uneven, and so easily bridging 

 over any small cavities in it. 



Calices usually round, -S-'O mm. in diameter, in the depressions 

 polygonal and still smaller. Cell-walls very thick, obtuse and 

 solid, often as broad as the calices, but in the valleys quite thin 

 and angular. Upper edge of the wall covered with low, rough, 

 blunt spines, giving them a very granular appearance. Septa 

 somewhat irregular, usually 12, generally rather thick with rough 

 sides, arising deep down in the calices and projecting for about a 

 third their diameter, primaries and secondaries sometimes fused at 

 the edges. Pali fused below to the septal edges, thick, rough, 

 blunt and extremely prominent, their summits almost level with 

 the top of the walls. There is visible no complete ring of corallum 

 joining the septal edges and pali, but usually 3-4 strands from the 

 pali run across the calicular fossa, meeting in the centre, where a 

 small, prominent, styhform columella is situated. 



In section the elements of the corallum present an open pali- 

 sade arrangement and are noticeably thin and delicate. 



