222 ANGELO ANDRES. 



or less developed in the various septa of the same individual. 

 Hanging in pairs upon the superior portion of every filament 

 are the well-developed, transversely furrowed "brauchia-like 

 organs,"^ or '' liver-organ."^ 



Towards the base of the animal the mesenteries run to- 

 gether (fig. 2, m) and form an anastomosing, spongy tissue. 

 As the behaviour of the mesenteric folds is, perhaps, the 

 most striking character of the polyp, I add drawings of six 

 transverse sections. Near the tentacles in the pharyngeal 

 region every septum is attached to the wall of the alimentary 

 tube (fig. 3) ; but in the proper gastric region only a few 

 preserve their attachment (fig. 4).^ In the so-called bran- 

 chial region the difference in size persists; the largest septa 

 bear the filaments and the branchiae, so that their sections 

 appear arrow-shaped ; all the septa enlarge at their base 

 and show a tendency to ramification (fig. 5). In corre- 

 spondence to the convoluted filaments this tendency increases, 

 and some of the branches anastomose together (fig. 6). 

 Farther dovvn the anastomoses become very frequent, till the 

 lumen disappears and a spongy, trabecular tissue alone 

 remains (fig. 8), Moreover, this spongy character extends 

 into the coenenchyma (see above), so that the buds or zooids 

 are in relation with the body of the mother through a real 

 system of enteric canals, and thus there is in this polyp a 

 point of connection (an analogy, if not a homology) between 

 Zoantharia, Alcyonaria, and Antipatharia. 



The histological structure of this polyp is closely similar 

 to that of the other Zoanthinse."* There is a cuticle, a sub- 

 cuticle, a cellular layer, a layer of connective tissue, a mus- 

 cular layer, and a mucous layer. 



The cuticle is an exceedingly thin, structureless membrane 

 (fig. 9, a). 



The subcuticle (fig. 9, h) is also thin, 0-030 mm., and homo- 

 geneous. 



Kolliker thinks that this layer has in the Zoanthinse no 

 individuated importance, and that it apparently belongs to 

 the cuticula.^ In this polyp, however, it is quite distinct 

 from the cuticle; and, to speak accurately, neither this nor 

 that layer should be called either subcuticula or cuticula ; 



> Dana, " Zoophytes" (' United States Exploring Expedition 1838-42'). 

 2 Lesueur, "Observations," &c. (' Journ. Acad. Nat. So. Pliiladclphia/ 

 i, 1817). 



^ Conf. Dana, loc. cit., plate 30, fig. 3 d, how different. 

 ■* See Kolliker, ' Die Biudesubstanz der Ccelenteraten.' 

 * Kolliker, loc. cit. 



