542 rESCEiPTioN of \Folygasirica. 



down the sheath. It lives but a short time when removed from its 

 native place — Brightwell. Size l-430th ; tree 1 -4th; stalt l-4th. 

 the thickness of the body. 



"We are happy to quote the valuable observations of our countryman, 

 Mr. Brightwell, of Norwich, as given in his original little work, en- 

 titled Fauna Infusoria of Norfolk, 1848. 



" Sept. 16th, 1846. Early in the morning of this day, we observed 

 one of the Zoothamnium arhuscula, a large old specimen, which had lost 

 all its small bell-shaped animals, but had several medlar-shaped buds 

 or ova remaining upon it. It was seen to detach from its stalks nearly 

 all these ova, which went off as free animals ; one of them soon after 

 settled at the side of the water-trough, and after agitating its anterior 

 ciHa, it suddenly, and with a kind of violent effort, opened into a 

 cup-shaped form, and darted about with great rapidity, occasionally 

 settling, and darting off again. 



"At nine in the morning, one of these buds, or ova, was observed 

 fixed to the glass by a sheathed pedicle, a ciliary motion became 

 perceptible at the top of the bulb, and at ten it had divided longi- 

 tudinally into two buds, each supported by a short stalk. The ciliary 

 motion continued in the centre of each of these two buds, which by 

 degrees expanded longitudinally, and at twelve had become four 

 buds. By four, p. m., these four buds had divided in like manner 

 and increased to nine, with an elongated foot stalk, and interior 

 contractile muscle. 



" During the development of another specimen, the stalk appeared 

 to have transverse ribs or joints, and whilst a di'awing was making, 

 gradually bent downwards, and all the buds severally detached them- 

 selves from it, and went off as free animals, leaving only the 

 bent stalk. " In this interesting process we see something analogous 

 to what Stcenstrup describes as ' a mode of development by means of 

 nurses or intermediate generations.' 



"This mode is described as that in which an animal produces a 

 progeny permanently dissimilar to itself, but which progeny produces 

 a new generation in itself, or its offspring, returning to the form of the 

 parent animal. It will be seen that this development differs from 

 that of metamorphosis, in the circumstance of tlie intermediate 

 jiuimal (the nurse) being itself a permanent and producing form. 



"To shew this to be the case with Zoollmnniam, it would bo 



