494 MB. H. M. BEENARD ON 



Reference to the digrams shows that they occur iu a definite 

 order, and that, in their development, they are closely associated 

 with the fusions of the septa. 



Passing over the cases of those Porites with septa arranged 

 as in fig. 1 (p. 492), and each with a slight paliform swelling, and 

 therefore with traces of 12 pali, the number is limited to eight as 

 shown in fig. 4. Of these eight, the four which arise at the 

 points where the septa meet in pairs are usually much larger 

 than the rest (PI. 35. fig. 1). They may be very large indeed. 

 as compared with those arising from single septa. When the 

 large palus is formed by the fusion of the three septa, as shown 

 in fig. 5 (diagr.), we have, with the four large ones at the points 

 of fusion of the pairs, five large pali. Whenever we have a ring 

 of five large pali, we know where and how they arise, viz., at 

 the five points in which the septa fuse (see many of the rings 

 of pali, Plate 35. figs. 3 & 6). Among these will be seen 

 many in which there is a small extra palus, making five principal 

 pali and one minute palus. The last is that on the directive 

 septum, which remains single as shown in fig. 5 (diagram). 



In Plate 35. fig. 6, it is easy to see the large pali arising from 

 the points of fusion of the septa, and here and there having the 

 V-ahape described by Dana. But this arises not from the fusion 

 of granules, as the great American naturalist believed, but from 

 the fact that the fusing septa are slightly exsert *. 



As the pali will have to figure in all future specific descriptions, 

 it is necessary to name them. I propose therefore to call those 

 which arise at the points of fusion of the four pairs, the four 

 ''Principals.'' The directive palus which often takes part in the 

 triple fusion may be called the ' Directive principal.'' The rest 

 may be called Supplementaries, and we have a directive supple- 

 mentary and two lateral supplementaries ; one or both of these 

 last-named may fuse with the directive principal. 



It should be noted that no palic formula seems to be constant 

 throughout all the calicos of a stock. When describing the 

 formula of any species of Porites, all that is meant is that there 

 is apparent in the colony a tendency to produce that particular 

 formula. 



Having now described the septa and the pali, we may return 



* This prominence of the pali and septa in many of the Porites with 

 developed coenenchymas was thought to be another generic distinction of 

 Synaraa, but the point is an unimportant one. 



