48 ZOOPHYTES. 



commencing immediately at the mouth, and others rising to fill up 

 the spaces between them as these diverge Although so unlike the 

 type in external shape, yet the actual structure is closely similar, for 

 the Fungia is nothing but an Actinia spread out laterally into a broad 

 flat disk. The inequality in the lamella? is much greater, though of 

 the same character, and the tentacles are more widely scattered, so as 

 to lose all appearance of being in series. The connexion between the 

 formation of a tentacle and a new lamella within the animal, is finely 

 exemplified in the Fungia; for each tentacle rises where a new ridge 

 reaches the surface, and their formation is constantly going on as 

 the animal enlarges and new ridges rise. This may be seen by 

 reference to the figures of Fungiae on plates 18 and 19, where 

 the small prominent tubercles scattered over the surface are the 

 tentacles.* 



The close relation of the Fungia to the common Actinia is thus 

 evident; yet in the actual form of the visceral cavity they are quite 

 unlike. Instead of a cylindrical space, divided into shallow compart- 

 ments by erect fleshy lamella?, we have here long horizontal compart- 

 ments, commencing at the mouth, and as they enlarge outward, con- 

 stantly subdividing by the growth of new lamella? : these lamella?, for 

 a while before rising to the disk, range along the bottom of the cavity. 

 Unlike the Astraeas, the Fungia? never cover the contracted tentacles 

 by the involution over them of the margin or surface from which they 

 rise; there is actually no margin to the disk in these animals: more- 

 over, in compound species, the visceral lamella? of adjoining polyps 

 are continuous from one to the other, and it is probable that the sub- 

 divisions of the visceral cavity are also directly continuous, so that in 

 these compound Fungia? we appear to have a community of visceral 

 cavities, as in the Hydroidea, differing from the latter, however, in 

 having the communications by lateral or interseptal spaces, instead 

 of by the lower extremity of the cavity. In the Astra?as, the same 

 communication in effect takes place, though less perfect, through the 

 open pores or lacunes, which pass laterally from one polyp to another. 

 The Fungia? afford the nearest approach, among zoophytes, to the 

 Acalepha?. 



There is often in a Fungia, a line running from one or more sides 

 of the oblong mouth to the circumference, along which some of the 



* On account of the small size of these organs, it has been denied that they are tenta- 

 cles. Yet, whether so called or not, they correspond to the tentacles of the Actinia? ; and 

 in some species of Actinia they are as short and scattered (see plate 4, figure 32). 



