8 Mr. J. E. Dueiden on 



Colour. — The colour of the polyps when retracted is deter- 

 mined by that of the vesicles, and may be light blue or light 

 brown ; the vesicles, when not fully extended, are generally 

 pale blue in colour, tlie thickened bands and papillse a dull 

 white, when inflated to their utmost are a pale brown. In 

 extension the capitulum, tentacles, and disk are nearly 

 colourlesf!, but a slight brown tint can be distinguished ; the 

 column- wall in the vesicular region, as well as the pedal disk, 

 is brown ; the lips white. 



Dimensions. — The dimensions are very variable, according 

 to the state of retraction or extension. The diameter of the 

 base may be as much as S5 centim. ; an average diameter 

 of specimens retracted in formalin is 1'8 centim. ; height of 

 retracted specimens about 0'5 centim. ; length of extended 

 inner tentacles 3*5 centim. ; vesicles when inflated may be 

 0'7 centim. in diameter and 1 centim. in length. 



Locality. — The species is met with sparingly throughout 

 Kingston Harbour, Jamaica, attached to weeds in shallow water. 

 Around the shores of the canal behind Port Royal, and at 

 certain other places in the harbour, it occurs in abundance. 



Activities. — The usual condition presented by the animal 

 is that of a flattened extended group of bluish-white or pale 

 brown vesicles towards the free end of elongated marine 

 plants, such as T/mlassia, to which the colours offer a marked 

 contrast. The polyps are elongated along the length of the 

 weed, or partially folded round it, and generally exhibit no 

 appearance of disk, tentacles, or column-wall. They well 

 bear out Andres's statement of resemblance to Nudibranchs. 

 They occur near the surface in shallow water around the 

 shores, and occasionally detach themselves and move to new 

 positions, or, more rarely, may float on the surface of the 

 water with the base upwards. Less commonly they are fully 

 extended, the elongated tentacles in constant motion or grace- 

 fully overhanging. The vesicles are very changeable in size 

 and appearance according to the amount of inflation ; in the 

 same polyp some may be inflated and others not at the same 

 time ; often they and the tentacles are quite limp. The urti- 

 cating powers are considerable, being sufficient to pierce the 

 skin of the hand. It is a very delicate and sensitive species, not 

 bearing confinement well. An asexual method of reproduc- 

 tion is effected by the detachment of fragments of the body- 

 wall from around the margin of the base and column. 



Base (PI. T. fig. 3). — The three layers of the base are 

 clearly distinguishable. The nuclei of the ectoderm are 

 arranged mostly in a narrow zone a little below the surface, 

 the tissue nearer the mesogloea not staining so deeply. The 



