Part II. — StichodacttfUnce and Zoanthece. 163 



peristome somewhat elevated. Towards the periphery the tentacles are so close 

 that the actual surface of the disc can scarcely be seen ; centrally, as the rows 

 begin to cease, the disc itself is more exposed. In a large specimen, 160 rows were 

 counted near the periphery, the longest row containing 24 tentacles, all of which 

 communicate with the same mesenterial sjiace ; interspaces may occur at almost 

 any point showing where tentacles have failed to develop. Usually no serial order 

 in the lengths of the various rows is apparent, though in young examples an 

 arrangement in three or four orders can sometimes be made out. In larger speci- 

 mens, all kinds of iiTCgularities in the way of omissions may occur ; a bifid 

 example is occasionally come upon, and small tentacles are seen in process of 

 development all round the margin. 



A single outermost cycle alternates with all the radial rows (PL xi., fig. 7). 



Viewed from within, in dissections, the rows of tentacles are seen to communi- 

 cate with the endocoelic chambers by large, closely arranged, circular apertures; 

 the outermost cycle is exocoelic in position. The tentacles are short and digitiform, 

 but vary a little in shape and size, according to the amount of distension ; some- 

 times they are quite collapsed. In the preserved condition the tentacles of some 

 polyps retain the finger-shape in all, while, in most, they become short and vesicle- 

 like, a denser apical area denoting the extent of the distribution of the nematocysts. 

 The surface of the tentacles may be very finely fluted, from apex to base, in 

 preserved specimens, and the discal ectoderm forms still finer ridges and furrows. 



The mouth is large and oval ; two gonidial grooves are always present, readily 

 distinguished by their thick lips. In large polyps three grooves are sometimes 

 met with. 



Tlie base is white or cream-coloured ; the column white or cream below, and a 

 little darker above. Sometimes large, irregular, green patches may occur on the 

 column and distally irregular vertical rows of small, oval-shaped, green areas 

 represent the verrucae, the number and closeness varying in the same specimen 

 in different rows. The disc may be a lighter or darker olive brown, and the 

 tentacles are the same, but irregular patches of different intensity are usually 

 exhibited. 



The peristome is a brownish yellow, the lips a rich yellow, the stomodseal 

 wall white. 



The waters at Port Antonio contain a remarkable colour variety. The entire 

 column and disc, with the exception of the green verrucae and a slight brown tint 

 on the peristome, are colourless and perfectly transparent. The tentacles, on the 

 other hand, are a clear, delicate, sulphur yellow. It is scarcely possible to imagine 

 a form differing more in colour from the ordinary condition ; seen on the dark 

 sea-floor, they are very attractive objects. Odd brown tentacles may be scattered 

 among the yellow ones, and one or two examples showed considerable areas of 



