UNKNOWN ATLANTIC OR WEST INDIAN PORITES. 93 



distinct. The walls are straight ; where a wall-thread is visible, it is very tliin and only 

 faintly zigzag. The septa branching from its angles are thin and short, but swollen at their 

 tips. The chief variation in the coral is due to the swelling of the peripheral portions of the 

 septa into enormous granules, which then show like a row of large knolis along the wall, 

 mostly obscuring the wall-thread. Within this row of knobs there is, though very irregularly, 

 a second ring of (septal) granules, and within this again the pali (5) with central tubercle. 

 The fusions of the septa are obscured, the whole surface being very neatly granular.- The 

 granules, seen sideways, rise like short bristles, and are neatly arranged into concentric rings 

 within polygonal areas marked off by rather larger granules. The section of one of the erect 

 processes shows a small, central, streaming axis surrounded by stout, dense, in-egular reticulum. 



This coral appears as if it were the expanding base of a branching form, and in order to 

 have a safe foothold, it had nearly to enckcle the stem, and in doing so, cover up a stock of the 

 coral last described. The neat mosaic of granules or short bristles is not too crowded, but 

 sufficiently spaced and differentiated as to render the calicles conspicuous. This kind of 

 surface is quite peculiar and differentiates the form especially from the associated Poritcs 

 found in the same specimen, and described as No. 15. The upright processes had only just 

 started ; the one persists as a small irregularly mammillate process, and the other is broken 

 off, but appears to have been about the same size. It is possible that laoth of these may liave 

 been stimulated to growth by Balanids and thus not be the beginnings of true branches at all ; 

 on the other hand, the calicles are not like those usually associated with West Indian 

 massive or explanate corals. 



a. On Gorgonid skeleton in one small stock. Zool. Dept. 43. 3. 6. 98, (part). 



Specimen h. 



Description. — The upper surface rises into a nearly straight row of large loljes or knobs, 

 arranged along the length of the coral as it encircles the Gorgonid skeleton ; so close are these 

 that any forking or bulging has in each case to grow out laterally. Most of them have been 

 distorted by Balanids. They, with their secondary knobs, rise about 2 ' 5 cm. liigh and seem to 

 be about 1 • 5 cm. in diameter when they first start ; for the most part, then- tips are blunt 

 and round. 



The calicles are small, 1 to 1 • 25 mm. in diameter, very angular, conspicuous, and not very 

 shallow. The walls are straight, thin and conspicuous, raised as straight or irregularly zigzag 

 threads. The septal points projecting from it are few and minute, and even on the basal 

 expansion the septa are not conspicuous round the uppermost edge; they start below it. 

 Within and close to the walls is a ring of septal granules, and within that the pali, all small 

 and ii-regular, and with a central tubercle. The fusions of the septa are deej) down and 

 obscured. 



A section of a knob near the base shows great irregularity of solidification, that is, it is 

 not confined to the cortical layer, though there it is most conspicuous, but intermingled with 

 patches of more open reticidum. 



