116 M. E. Hiickel on the Organization of Sponges^ 



the stomachal cavity and each perigastric radial chamber. 

 Thus the ''''person " of Cyathiscus divides into a radial system 

 of antimerajjust like each developed coral-j)erson. 



That the formation of antimera occurs frequently in the 

 sponges generally, and that thereby a still closer approxima- 

 tion to the corals is eftected, has hitherto been entirely over- 

 looked, Miklucho having only last year called attention to it 

 (/. c. p. 230). In Axinella polypoides^ Osculina polgstomella^ 

 and many other sponges — among fossil forms, especially in 

 Coeloptychium lohatum^ Siphonia costata, &c., they strike one 

 at once. These " radial " sponges are true " lladiata " no less 

 than most corals. It is evident, however, that, from a tecto- 

 logical point of view, the sponges in which antimera are so 

 distinctly differentiated rise no less than the more highly deve- 

 loped corals above the lower sponges, in which no formation 

 of antimera occurs. 



Consequently, except the higher degree of histological dif- 

 ferentiation in most corals, there remains not a single character 

 Avhich completely separates the sponges from the corals. Even 

 the tentacles sm-rounding the mouth, which have hitherto 

 appeared to be the exclusive property of the corals, begin their 

 development in certain sponges. At least I would regard as 

 incipient tentacles the extremely remarkable curled and fringed 

 '^ papilla? " which form a circlet smTOunding the mouth-open- 

 ing of Oscvlina jjolystotnella, one of the most remarkable of 

 sponges. Moreover less importance is to be ascribed to the 

 tentacles of the corals, as secondarily developed appendages, 

 because even corals occur in which they are almost wanting 

 or developed only in the form of rudimentary buttons (e. g. 

 Antip>athes). 



That the conditions of stocJc-formation or cormogeny are 

 exactly the same in the corals and in the sponges scarcely 

 needs to be particularly mentioned. It is precisely in this 

 respect that the agreement between the two classes is so 

 striking that it was this principally which led the older natu- 

 ralists to unite the sponges and corals in their classifications. 

 In the sponges we find no less multiplicity than in the corals in 

 the combination of the " persons "to form stocks ; and even the 

 special modifications in the stock-formation which are produced 

 by the multifarious forms of incomplete division and gemmation 

 in the corals are reproduced in the sponges. Only one peculia- 

 rity pertaining here may be specially indicated, because it has 

 repeatedly led to singular misinterpretations. This is the 

 formation of peculiarly reduced stocks by the groioing together 

 or concrescence of the branches, i. e. "j!?e/\w>is." Just as in the 

 well-known fan-corals (e. g. Iihip>idogorgia fabellum) the pe- 



