422 



Microscopical Essays. 



4 now appears fwelled, as at c, Fig. 21 ; the arms fhoot out from 

 this end 3 at firft three or four points only begin to (hoot, as at c, 

 Fig. 20, and while thefe increafe in fize, others appear between 

 them ; they can feize their prey, and eat before their arms have 

 done growing. In the* height of fummer, the arms will often 

 begin to moot in twenty-four hours ; but in cold weather it will 

 be fifteen or twenty days before the head is formed. 



Fig. 22 reprefents a polype that was cut clofe under the arms ; 

 this became alio a complete animal in a little time. 



The fides of a polype, that has been cut longitudinally, roll 

 themfelves up in different ways, generally beginning at one of the 

 extremities, rolling itfelf up in a heap, as at Fig. 19, Plate 

 XXIII. B, with the out fide of the fkin inwards ; it foon unrolls it- 

 felt and the cut fides form themfelves into a tube, whereof the edges 

 a b and e i, Fig. 15, on both fides, meet each other and unite. 

 Sometimes they begin to join at the tail end, at other times the 

 whole fides gradually approach each other. The fides join fo 

 clofe, that from the firft. moment of their junction no fear can be 

 difcovered. 



Fig. 14, Plate XXIII. B, reprefents a polype partly joined, as 

 at i b, the part c a e not yet clofed. 



Fig. 29, Plate XXIII. B, reprefents a polype, the heads of 

 which have been repeatedly divided, by which means it becomes 

 literally a hydra. 



fig. 24 



