Microscopical Essays. 547 



green, there are two little bright veficles in the middle, it's mo- 

 tion is languid. It is but rarely met with, and then moftly in pure 



X. Bursa ria, 



Vermis fimpliciffimus, membranaceus, cavus. A very fimple;, 

 hollow, membranaceus worm. 



119. Burfaria Truncatella. 



Burfaria ventricofa, apice truncata. Ventricofe burfaria, the 

 top truncated. 



An animalculum that is vifible to the naked eye, white and 

 oval, truncated at the top, where there is a large aperture, the 

 ' opening that forms the aperture defcending towards the bafe ; at 

 the bottom of mo ft; of them there are three or five yellow eggs. 



It moves itfelf at pleafure from right to left, and from left to 

 right, afcending to the fuperficies of the water in a right line ; 

 fometimes it rolls about while defcending. i 



• 120. Burfaria Bullina. 



Burfaria cymb^formis, antice labrata. Boat-fhaped burfaria, 

 the fore-part formed into a lip. 



A pel- 



