Microscopical Essays, 



549 



A fubfpheric hollow animalculum, the lower end furnifhed 

 with black molecules of various fizes. the fore-part with obfcure 

 points, the reft entirely empty, and the middle very pellucid; 

 it moves (lowly from right to left. 



XL Cercaria, 



Vermis inconfpicuus, pellucidus, caudatus. An invifible pel- 

 lucid worm with a tail. 



124. Cercaria Gyrinus.. 



Cercaria rotundata, cauda acuminata. This cercaria is round, 

 and has a (harp tail. 



The body is white, gelatinous, without any traces of interlines ; 

 the fore-part fomewhat globular, the hind-part round, long, and 

 pointed ; fometimes it appears a little comp relied on each fide. 

 The tail is in a continual vibration while it is fwimming, like that 

 of the tadpoles. It feems very fimilar to the fpermatic ani- 

 maleula. 



125. Cercaria Gibba. 



Cercaria fubovata con vex a, antice fubacuta, cauda tereti. 

 Somewhat of an oval fhape, convex, the fore-part rather acute, 

 the tail round, 



It 



