Septembeb 20, 1907] 



SCIENCE 



375 



does not agree. The number of granules on 

 the septal margins of many Porites is variable, 

 varying, however, within narrow limits, from 

 one to two, or at most three or four. Speci- 

 mens broken so as to permit the study of septal 

 faces through considerable distances, several 

 centimeters, show that the wall trabecule is 

 persistently vertical and continuous, and the 

 columellar trabecula is often definitely persist- 

 ent throughout the length of the corallite. 

 The intermediate trabeculse, however, are not 

 always vertical, but often incline inwardly, 

 new trabeculse arising in the angle between the 

 outermost septal trabeculse and the mural tra- 

 beculse of a given calice. The innermost of 

 these trabeculse form the pali, those outside 

 the palar ring form the septal granules, which 

 sometimes vary in number for the same calice. 

 Typical Porites has septa entirely homologous 

 with those of the other Madreporaria in which 

 the line of trabecular divergence is coincident 

 in position with the wall, but in which the 

 outer portion of the septum is suppressed.' 

 Although the reviewer does not agree with 

 Bernard in his conclusions on the morphology 

 of the Porites septum, it should be emphasized 

 that he was the first one to call attention to 

 the importance of studying the granules on 

 the septal margins and the details of the walls 

 in the genus. 



Synarwa Verrill is referred to the synonymy 

 of Porites; the ccenenchyma of the former is 

 regarded as formed by fused costal prolonga- 

 tion of the septa. 



An hypothesis, proposed to explain the rela- 

 tionship of tabulae to gemmation, may be 

 briefly expressed as follows : a corallite divided 

 into sections by transverse tabulae was not 

 occupied by a single individual, but by a suc- 

 cession of individuals. Each segment, bound- 

 ed above and below by a tabula, was occupied 

 by an individual which had originated by 

 gemmation from the individual that occupied 

 the immediately preceding segment. The 

 strobilation of Aurelia and the peculiar bud- 

 ding of such forms as Ptychophyllum (the 



" This subject is more specifically discussed in 

 the reviewer's " Madreporaria of the Hawaiian 

 Islands and Laysan." Bulletin 59, U. S. National 

 Museum, pp. 169, 170, 1907. 



name of this genus is not mentioned) are cited 

 to sustain the hypothesis. The discussion is 

 continued with the remarks : 



If this is a true account of the phenomenon, 

 that the earlier cruder form of metamerism with 

 its piles of obviously discrete calices, passes grad- 

 ually into a continuous skeleton, the original 

 segments of which are now so disguised as to be 

 seen only in the succession of the tabulse, we shall 

 have, in the formation of every such coral, to dis- 

 tinguish two methods of growth. In the earliest 

 stages of its individual development the growth 

 will be normal growth de novo from the larva, 

 with the gradual withdrawal of the expanding 

 polyp from the cup which is progressively too 

 small for it. This results in the deposition of one 

 series of tabula. When the normal size of the 

 adult is reached the growth is different, and can 

 no longer be described as a growth of the indi- 

 vidual with withdrawal of the enlarging polyp 

 from too small a skeleton, but the deposition of a 

 new skeleton upon the framework of the old, the 

 new skeleton belonging to a new individual polyp 

 which comes into existence in some way by gem- 

 mation from the old, but the only visible sign is 

 still seen in another series of tabulae, differing 

 from the first in that there is now no increase in 

 the diameter of the stock. 



Calicinal budding and the rejuvenation in 

 both solitary and compound corals are well- 

 known phenomena. The presence of tabulae 

 and dissepiments (tabulse are only horizontal 

 dissepiments) in a corallite in which the septa 

 and walls are definitely continuous, is ex- 

 plained by the polyp's needing a new basal 

 support after the septal and mural margins 

 have been built to a certain height, therefore 

 the polyp draws upward and forms a new bot- 

 tom to the calice. To hypothecate successive 

 budding to explain the occurrence of tabulae 

 and dissepiments in coralla of the type indi- 

 cated is unnecessary. 



Bernard's opinion on the phylogeny of the 

 PoritidsB may be introduced here: they are 

 considered to have a common ancestry with 

 the Madreporidse and Eupsammidse. 



Bernard's Method of Arranging and Desig- 

 nating his Specimens. — -The extreme difficulty 

 of recognizing and defining species of the 

 Madreporaria is known to practically every 

 one who has given serious attention to the 



