METOPIDIA ACUMINATA. 



65 



a Metopidia^ with a firm shell, a forked jointed 

 tail, and a projection in front which worked like 

 a pick-axe among the decaying weed. There were 

 likewise specimens of the long-necked animalcules, 

 (Trachelii,) groups of Vorticella, some specimens 



A, Metopidia acuminiita, as drawn by Mr. Gosse. B, Specimen as seen at]d 

 described in text; c, Mouth or gi/zard. 



of Vol vox, and a small Trichodina pedicidus, which, 

 when magnified two hundred and sixty linear, was 

 about the size of a sixpence, and equally round. 

 The edge was beautifully fringed with a circle of 

 cilia; in an inner circle was a row of locomotive 

 organs, and the centre exhibited vacuoles constantly 

 opening and shutting. This creature, as before 

 explained, is often four.d, as a parasite upon tlie 



