372 J. E. Dueeden — Jamaican Actiniaria : Part I. — Zoanthece. 



Parazoanthus Swiftii (Duchassaing and Michelotti). 



(PI. XVII. a, fig. 11.) 



Gemmaria Swiftii, . . . Duchassaing and Michelotti, 1860, p. 331, pi. viii., 



figs. 17, 18 : 1866, p. 138. 

 Polythoa (sir. s.) axinellce, Andres, 1883, p. 311, pi. x., fig. 7. 



Form. — Polyps very short, cylindrical, mammiform in retraction, erect, firm, 

 smooth, rising from small band-like branching patches of coenenchyme incrusting 

 the surface of a sponge ; sometimes the polyps are arranged in a single linear 

 series, at other times the coenenchyme is expanded, and two or three individuals 

 may occur abreast. Capitulum with twelve serrations at the apex. In partial 

 retraction these appear as so many wedge-shaped ridges, with intervening 

 furrows, around a central orifice ; in full retraction the capitular ridges are 

 scarcely visible, and the polyps are rounded above. 



Tentacles minute, entacmseous, acuminate, dicyclic, twelve in each row, the 

 outer alternating with the serrations, overhanging in extension. Disc concave, 

 transparent, with mesenteries showing through ; mouth slit-like and capable of 

 considerable eversion ; lips crenate ; oesophagus shows longitudinal mesenterial 

 lines ; oral cone may be considerably elevated. The usual condition of the polyps 

 appears to be that of retraction. 



The coenenchyme is smooth, thin, in irregularly shaped meandering ribbons 

 or patches firmly incrusting and partially embedded in the sponge. 



Colour. — Coenenchyme and column-wall are a bright orange yellow, lighter 

 on the upper part of the column ; tentacles are pale yellow ; disc a darker, and 

 lips a bright yellow. The parts are sand-coloured where the ectoderm is rubbed 

 off. The bright orange colour gives to the colonies a marked contrast with the 

 dark green sponge. 



Dimensions. — Height of polyps above the coenenchyme varies from 0*15 cm. 

 to - 3 cm. ; diameter of expanded disc 04 cm. ; diameter of column in contrac- 

 tion 0*2 cm. 



Locality. — Jamaica : Obtained growing in small colonies on a large, erect, 

 blackish-green, branching sponge collected in water of about two fathoms around 

 Rackum Cay; also from the shallow waters S. W. of Lime Cay, living on the same 

 species of sponge. 



Range. — St. Thomas (Duchassaing and Michelotti). 



Column-wall (PI. xx., fig. 5). — The column-wall is very thick. The cuticle 



