NEW GENUS AND SPECIES OF ZOANTHINA MALACODERMATA. 225 



dices, dendritic in form, not brush-like ; at the pyloric ridge 

 there is a distinct muscular sphincter. The branchia-like 

 organs are, histologically, mere outgrowths of the mesenteric 

 folds, as these are of the body-wall. I did not see the canals, 

 which, according to Dana, exist on every transverse stripe. 

 The filaments present no lumen ;^ they have a very thick 

 layer of round cells and of nematocysts ; the latter have a 

 regular radiating arrangement, and seem quite similar to 

 each other and to those of the body-wall and tentacles. The 

 three specimens I have examined contained neither ova nor 

 spermatozoa. 



From all these characters it appears clearly that this polyp 

 belongs to the group of the Zoanthina nialacodermata, and 

 therefore is akin to the genera Polythoa, Zoanthus, Mam- 

 millifera. Pales, Isaura, Ormia. I have only been able to 

 examine specimens of the first four genera,^ yet have no 

 hesitation in asserting that the subject of the present descrip- 

 tion is a decidedly new genus, at least so long as the already 

 established allied genera retain that rank. 



That the reader may judge, I expose the characters of 

 the whole group — dichotomously, for brevity's sake : 



A. Coenenchyma involving the whole polyp. — Polythoa.^ 



B. Coenenchyma basilar only. 



a. Persistent — adult individuals in colonies. 



a. Regular — colonies of numerous individuals. 

 ■^ Expanded, flat. — Mamillifera.'^ 

 ■^"^ Slender, cylindrical. — Zoanthus} 

 /3. Irregular — colonies of few individuals. — 

 Pales.^ 



b. Not persistent — adult individuals isolated. 

 N a . Tentacles in two cycles. 



^ Peristome without velum. — Panceria. 

 * * Peristome with velum. — IsaurusJ 



^ Conf. Leuckart, ' Beit rage zur Kentniss der wirbellosen Tliiere ;' and 

 Delia Chiaje, Rapp, Blaiuville, Cuvier, &c. 



2 I am very much obliged to Prof. Owen and Dr. Giinther, who gave me 

 opportunity to observe the specimens of the British Museum. 



' Dana, loc. cit. Polythoa . . . polypis latere coadunatis ; genus with 

 the ancient Maniillifera and Corticifera of Lesueur. Gray s. i. Polythoa 

 .... base subcylindrical, creeping (!). 



■• Lesueur, loc. cit. Dechassaing e Michelotti, s. i. Lamouroux (' Ex- 

 posit, methodique des genres de I'ordre des polypiers,' Paris, 1821). 



* Gray, s. i. Dechassaing e Michelotti, s. i. 



* Gray, ' Proceed. Zool. Soc. London,' 1867 ; new genus. 



" Lavigny, " Polypes d'Egypte," Audouin's ' Expl.' Gray, ' Spic, Zool.' 

 Lamouroux, loc. cit. 



