60 ZOOPHYTES. 



In an early stage it appears as a white globular head, crowning a 

 short stem, one scarcely half a line high. When more advanced, it gene- 

 rally occurs, or, perhaps, more readily attracts notice, when in numerous 

 colonies of individuals rising about a line and a half. Then it consists of 

 a smooth white stem, crowned by a variable campanulate hydra, with 

 fourteen ciliated tentacula. The stem of certain specimens has appeared 

 prickly, sometimes invested by foreign matter ; and I have thought a web 

 uniting the roots of the tentacula discernible. 



At this stage the Pedicellina generally dwells in numerous societies, 

 implanted on the twigs of other zoophytes, or distributed profusely over 

 shells.— Plate XX. Fig. 1. 



The adult rises half an inch in height, by a smooth bare stem, with 

 twenty or a greater number of hydrae, meagrely and irregularly disposed 

 on branches or pedicles to right and left, on one or on both sides. But 

 such luxuriance is very rare. Among a multitude of specimens, I have 

 seldom found any with even a few animals. 



It is only in early stages, when the hydra is solitary, that it can be 

 most satisfactorily inspected. Then, the head is discovered to be of an 

 extremely variable shape, frequently distorted in an uncommon manner, 

 — such as I have not seen in any other zoophyte — and next restored to 

 its symmetry. Sometimes it is flattened, or it is preternaturally en- 

 larged on one side, swollen, contracted, or otherwise, at the will of the 

 animal ; and always presenting considerable diversity of aspect, either by 

 one, or by the various specimens of a colony. 



The action of the cilia bordering the tentacula is very distinct, where- 

 by a vortex, or a current attracting buoyant particles, conducts them up 

 the sides of the tentacula, or over their extremities, and then down into 

 the cavity of the mouth, dilating for their reception. This dilatation is 

 extraordinary, it equals almost the whole diameter of the head. Next, a 

 dark mass is tossed about within, fig. 2 : — and if now viewed from above, 

 the active operation of numerous cilia lining the cavity is discovered. I 

 recollect that, on exhibiting a favourable microscopic view of the various 

 peculiarities displayed by this subject to a very accomplished naturalist, 



