NEW GENUS AND SPECIES OF ZOANTHINA MALACODERMATA. 223 



the subcuticle is in this polyp undoubtedly only a continua- 

 tion of the mesodermic connective tissue, while the cuticle 

 may be considered simply as a differentiation or hardening 

 of its external surface. 



The cellular layer (fig. 9 c) or ectoderm has its elements 

 gathered together in conspicuous groups of thirty to fifty 

 cells each. These groups are entirely surrounded by the 

 connective tissue, which on the surface towards the cells 

 differentiates a peculiar membrane, like the cuticula of the 

 external surface. The elements are granulations and cells. 

 The former are various in size, and perhaps of pigmentary 

 nature. The latter present three forms, which seem to be 

 only three different stages of a single, identical element, 

 viz. A (fig. 10, a), round, apparently isolated cells, with 

 highly refracting nucleus and membrane; B (fig. 10, h), 

 similar cells, Avith a prolongation towards the inner side of 

 the group; c (fig. 10, c), nematocysts of ellipsoidal shape, 

 perpendicular to the external surface of the animal, contain- 

 ing a spirally wound filament ; they are like the nemato- 

 cysts of the seventh kind of Haime,^ or of (he fourth of 

 Mobins.^ The similarity of these groups of elements scat- 

 tered on the whole surface of the body with the heaps of 

 ** Korner, Zapfen, Kugeln," described by Rotheken in the 

 bourses marginales as eyes,^ is very striking ; and this may, 

 perhaps, add a new argument against his hypothesis to those 

 already urged by Ludwig.* 



The connective tissue (fig. 9, d) is gelatinous (Kolliker), 

 and presents cells, canals, and fibres. 



Of the cells (a) some are very distinct masses of proto- 

 plasm, with a clear nucleus and nucleolus (fig. 11); {b) 

 some are only isolated nuclei with one or two nucleoli, and 

 with more or less slight traces of protoplasm (fig. 12) ; (c) 

 some appear as irregular, finely granular bodies, with crys- 

 talline spicules of carbonate of lime, and usually adherent to 

 a fibre (fig. 13) ; {d) some present only a relatively large 

 mass of the same salt and no trace of protoplasm, or only a 

 very trifling one (fig. 14). All these crystals are not so 

 peculiarly shaped as in other Zoanthinse f still they are 

 homologous with them and with the sclerites of Antipatha- 



' J. Haime, "Mem. sur le Cerianthe" ('Ann. sc. nat,,' 4, i). 

 ' K. Mobins, " Bau und Eutwick. der Nesselkapseln " (' Abh. nat. 

 Vereins Hamburg,' v). 

 ^ Schneider und Rotheken, *S. B. oberhess. Ges.,' 1871. 



* Hubert Ludwig, ' Nachrichten d. k. Ges. d. Wiss. Universitat Got- 

 tingen,' 1875, No. 18. 



* Kolliker, loc. cit. 



