TPOLYPIFERA. 



39 



themselves mouth downwards, and crawl by 

 means of their tentacula, but our observations 

 have failed to confirm these remarks. 



The substance of the Actinia is entirely 

 composed of transverse and perpendicular 

 muscular fibres, which cross each other, the 

 meshes of this interlacement being occupied 

 by a multitude of granules, seemingly of a 

 glandular nature, giving to the surface of the 



polype, which is covered with a gelatinous 

 membrane, a tuberculated appearance. Ex- 

 ternally this fibrous membrane forms the 

 parietes of the creature's body, expanding in- 

 feriorly into the basal disc, and superiorly, 

 after forming a sphincter-like ring around the 

 tentacula, is continued inwards to form the 

 tentacula themselves (fig. 46, a), and then, 

 becoming more delicate in its texture, reflected 



Fig. 45. 



Actinia alcyonoidea. (After Quoy et Gaimard.} 



into the interior of the body so as to form the 

 stomachal cavity (b). Extending between the 

 internal surface of the outer walls of the body 

 and the exterior of the stomach are numerous 

 longitudinal septa (c) r evidently the homo- 

 logues of the vertical partitions of the Alcyo- 

 nide (fig. 31, f), and were these calcified by 

 the deposition of stony matter in their interior 

 they would represent exactly the radiating septa 

 in the cells of the polypary delineated in/g.43. 



As in the preceding genera these mem- 

 branous septa support the organs of repro- 

 duction, which are constructed after the fol- 

 lowing manner.* 



The whole interior of the Actinia, between 

 the stomach and the muscular parieties of the 

 body, is divided by means of the septa into 

 numerous longitudinal cavities, each of which 

 communicates with the bases of two or three of 

 the tentacula around the mouth f and encloses 

 an ovary. Each ovary is composed of three or 

 four cylindrical and coherent tubes of extreme 

 delicacy, which, towards the base of the 



* Spix, Annales cht Museum d'Hist. Nat. torn. 13. 



f For an admirable diagrammatic representation 

 of the structure of Actinia, the reader is referred to 

 Dr. Sharpey's Article " CILIA," Vol. I. fig. 297. 



Section of'Actinie Clou." 



a, Tentacles surrounding the mouth j b, stomach ; 

 c, longitudinal septa prolonged and enclosing the 

 ovaries. (After Quoy et Gaimard.') 



D 4 



