428 Microscopical Essays. 



and he then fufpe&ed them to be a particular fort of infec\ bred 

 in animal bodies, or at leafl the embryos or eggs ©f thenv 

 2. Became he obferved them included in a membrane, like a 

 matrix, fo loofely, that by opening it with the finger, or a knife, 

 the internal bladder, containing the ferum or lympha, feemed no 

 % where to have any connection with it, but would very readily 

 drop out, ftill retaining it's liquor, without fpilling any of it. 

 2. He obferved that this internal bladder had a neck, or white 

 body, more opake than the reft of the bladder, and protuberant 

 from it, with an orifice at it's extremity, by which, as with a 

 mouth, it exhaufted the ferum from the external membrane, and 

 fo fupplied it's bladder, or flomach. 3. Upon bringing this neck- 

 near the candle, the neck moved and fhortened itfelfc Fig. 

 Plate XXI. reprefents one of thefe watery bladders inclofed in it's, 

 external membrane, it's fhape was nearly round, being only a little 

 depreffed, or flatted, as a drop of cmickfilver will be by lying on. 

 a plane. In Fig. 2 the neck is better feen j the external membrane 

 being taken off, an open orifice is found at it's extremity ; it 

 confifts of circular rings, or incifures, which are more vifible 

 when magnified, as in Fig. 3 ; it then appears granulated 

 with a. number of little eminencies all over the furface ; the 

 orifice at the extremity ferns to be formed by retracting itfelf in? 

 wards, and upon trial it was found to be fo ; for in Fig. 4, the 

 neck of this polype is xeprefented magnified and drawn out it* 

 whole length ; on opening it there were found withkLthe two- 

 firings a a, which probably convey into the ftomach the moifture- 

 and nourimment, which the animal, by protruding it's neck, ex- 

 tracts from the external membrane.* 



Hydra, 



* Hydra hydatula habitat in abdomine mammalium, ovium, fuum, murium, &Ci 

 inter peritoneum et inteftina, Vefica lymphatica-, pellucida, magnitudme pmrui 



getiolat^ 



