Part II. — Stichodactylince and Zoanthece. 141 



Water was freely emitted through the tubercles when the animal was com- 

 pressed in collecting, though it may be doubted if this occurs naturally. The 

 peristome is slightly raised, and the gonidial grooves are well-marked, the two 

 lips being thicker and lighter than the rest of the stomodseal walls. 



The polyps possess very limited powers of retraction ; the disc and tentacles 

 are not infolded. 



The colours are very variable, partly dependent upon the age of the specimens 

 and whether the tentacles are smooth or bear thickened bands — but all gradations 

 can be traced in an abundant series. The prevailing disc colours are brown and 

 green, often iridescent, with opaque white spots and blotches; those of the column 

 are scarlet and crimson on a white or cream ground. 



The base is white, or may exhibit bright, radiating* scarlet bands. The column 

 is usually cream white, with irregular, longitudinal patches of scarlet ; the verrucse 

 display a very pronounced deep crimson centre. The column-wall is light grey 

 in young specimens, darker above. In these small forms the tentacles are also 

 greyish, the thickenings appearing as transverse white bands. The concave, outer 

 aspect of the tentacles is white, and a V-shaped white patch, with the angle open, 

 occurs at the base. In some the thickenings are of the same brown colour as the 

 tentacle itself. The smooth tentacles are brown or reddish brown, with light 

 crimson tips, and three longitudinal lighter lines traverse the whole length. 



The disc bears white, green, and blackish patches ; a black or brown radial 

 patch occurs at the inner aspect of the base of each of the primary tentacles, and 

 two towards the base of the four next cycles. The peristome is usually iridescent 

 green. 



The dimensions are likewise very variable according to age. Many young 

 specimens were collected, in which the length of the column was only 1*1 cm., 

 and the diameter, 0*8 cm. When extended the disc is about 5"5 cm. across in 

 large examples, but may be as much as 9 cm. ; the length of the column is 

 generally about 6 cm.; the diameter across the middle, IT cm., and across the 

 base, 2 - 5. The innermost tentacles measure 0*7 cm. in length. 



The figure of this species given by Professor MMurrich (1889, PI. n., fig. 1), 

 represents the more usual appearances of the Jamaican specimens, and I have not 

 considered it necessary to add another. The marginal tentacles should, however, 

 be compared with that on PL x. of the present paper. 



Anatomy and Histology. 



The ectoderm of the base is a very deep, columnar epithelium, much broader 

 than either of the two other layers, and, in sections, is thrown into strong folds, 

 partly followed by the mesoglcea. Long, narrow, supporting cells are 



TKANS. HOT. DUB. SOC, N.S. VOL. VII., PAKI VI. T 



