336 Natural History of British Zoophytes. 



not equally fatal, for I have repeatedly seen Cyprides and Daphnise 

 entangled in the tentacula and arrested for some considerable time, 

 escape even from the very lips of the mouth, and swim about after- 

 wards unharmed ; perhaps their shell may protect them from the 

 poisonous excretion. — The grosser parts of the food, after some hours' 

 digestion, are again ejected by the mouth ; but, as already mention- 

 ed, the stomach is furnished with what in one sense, may be called 

 an intestine to which, according to Trembley and Baker, there is an 

 outlet in the centre of the base, and the latter asserts that he has, 

 " several times, seen the dung of the polype in little round pellets 

 discharged at this outlet or anus."* 



But the Hydra is principally celebrated on account of its manner 

 of propagation. It is of course like zoophytes in general, asexual ; 

 and every individual possesses the faculty of continuing and multiply- 

 ing its race, principally, however, by the process of subdivision. 

 During the summer season, a small tubercle rises on the surface, 

 which lengthens and enlarges every hour, and in a day or two de- 

 velopes in irregular succession, or in successive pairs, J a series of 

 tentacula, and becomes in all respects, excepting size, similar to its 

 parent. It remains attached for some time, and grows and feeds, and 

 contracts and expands after the fashion of this parent, until it is at 

 length thrown off by a sort of sloughing or exfoliation. These buds 

 sprout, in the common species, from every part of the surface of the 

 body, but not from the tentacula ; and very often two, three or four 

 young may be seen depending at one time from the sides of the fruit- 

 ful mother, in different stages of growth, every one playing its part 

 independent of the others. They are evolved with rapidity in warm 

 weather especially, and no sooner has one dropt off than another be- 

 gins to germinate ; " and what is most extraordinary, the young ones 



best microscopes, it has been found, that the polypus is neither provided with 

 teeth, nor any other instrument that could pierce the skin." Smellie's Phil, of 

 Nat. History, ii. 462 — The fact that fishes cannot be made to swallow Hydrse, 

 seems to prove the presence of some irritating quality in the latter — See Trem- 

 bley, Mem. 137. 



* Lib. s. cit. 27 He adds, — " Much the greater and grosser part of what 



the polype eats, is most certainly thrown out again by the mouth, after lying a 

 proper time to become digested in the stomach : and, for a good while, I ima- 

 gined there was no other evacuation ; but am now convinced, that the finer part, 

 in small quantity, is carried downwards through the tail, and passed off that way. 

 I believe, however, there is also another purpose to which this passage serves, 

 and that is, to convey a mucus or slimy matter to the end of the tail, for its 

 more ready adhesion to sticks, stalks, or other bodies." 



f Baker's Hist. 35. 



