358 Rev. T. Hincks on British Zoophytes, 



been deceived. I have observed very vigorous contractions of 

 the mantle at one extremity of the body. The movements of the 

 gemmule are irregular. Sometimes it creeps along, using its 

 cilia as feet ; at other times it swims pretty rapidly through the 

 water ; at others it tumbles over and over. Occasionally it floats 

 on its back with its cilia upward, and in this state resembles a 

 miniature boat. After a short time the cilia suddenly cease to 

 play, the creature becomes attached, and is gradually developed 

 into the cell and polype, which are to be the nucleus of an ex- 

 tensive colony. 



In about twelve days from the time of attachment I have seen 

 the polype issue from its cell, but the development probably 

 proceeds more rapidly under favourable circumstances. Imper- 

 ceptibly the body of the polype shapes itself within the mass. 

 The tentacles are first visible. Soon violent convulsive move- 

 ments are seen within. The front part of the cell is frequently 

 pushed out with much apparent force, so as to form a neck of 

 considerable length, and then suddenly retracted. There is no 

 appearance of an opening at this time. The tentacles become 

 very restless, and bend themselves about as if trying their powers 

 and impatient of confinement. Gradually the parts become more 

 defined ; the elongation and retraction of the fore part of the cell 

 continue, and at length the polype breaks from its captivity. 

 The number of arms at first I have found to be twenty-four or 

 twenty-five. 



In the cases which came under my observation a narrow band 

 of the granular matter, which composed the substance of the 

 gemmule, remained round the body of the newly-formed polype. 

 Some time before the development of the latter was complete a 

 small swelling appeared on one side,— the rudiment of a second 

 cell. A portion of the granular matter just referred to seemed 

 to pass into it and fill it. This swelling gradually increased, ex- 

 tending down the side of the original cell. Before development 

 had proceeded far, a third cell began to germinate from the se- 

 cond. A fourth was also in process of formation on the other 

 side of the primitive cell (PI. XIV. fig. 3). 



The internal structure may be studied to great advantage in 

 the newly-formed polype (PL XIV. fig. 4). The particles of food 

 are borne down the oesophagus at once (there is no gizzard) into 

 the stomach. There they are kept in constant agitation — whirl- 

 ing to and fro incessantly — and after a while are expelled and 

 driven upward again by the sudden contraction of the walls of 

 the stomach. This goes on with much regularity. The contrac- 

 tions of the stomach are very vigorous, the opposite sides almost 

 meeting when the expulsion of the food takes place. A mass of 

 undigested material gathers near the pyloric orifice, and is kept 



