458 



VARIATION IN FORM. 



toot of surface and having some branches more than three inches in length. It is in best 

 condition towards the end of summer. 



Fig. E represents a portion of the Plumatella considerably magnified, showing the 

 polypes in various stages of protrusion, some being seen withdrawn wholly into their 

 cells. Fig. F is a statoblast of the same species, .and fig. G represents a side view of the 

 same object. In fig. E the position of the statoblasts is seen as they lie in the tubes of 

 the polyzoary, connected with the vital organs of the inclosed polypes. It will be 

 noticed that this statoblast is without spines. 



POLYZOA, X. 



A Alcyonclla Jungosa. B. Alcyonella fungdsa. x C. Alcyonella fungosa. (Tentacles of a polype.) D. Plumatella repeiu, 



E. Plumatella repens. x F. Plumatella repens. (Statoblast. x ) G. Plumatella repens. (Statoblast, side view, x) 



H. Fredericella Sultdna. x I. Fredericella Sultana. (Statoblast. x ) K. Paludicella. L. Paludicella. x 



M. Paludicella. (Tentacles, x) N. Paludicella. (Tentacles, x) 0. Paludicella. (Tentacle, x x ) 



The sign x signifies that the object is magnified. 



At fig. H is shown the tentacular crown of a lovely polyzoa, called Fredericella 

 sultdna ; the former title being given to it in honour of M. Fr. Cuvier, the celebrated 

 naturalist, and the latter being earned by its graceful and queenly beauty. This is a 

 common British species, and is found plentifully in the Regent's Canal, where it may be 

 detected growing in tufts on submerged stones, plants, sticks, and similar objects. It also 

 inhabits rivulets, but seems to prefer tolerably still waters. As it is tolerably hardy, it is 

 useful to microscopists, who can keep it alive in a common vial of water and place 

 it under the microscope whenever they choose. At fig. I the statoblast of this species is 

 shown. 



Our last example of the Polyzoa is the Paludicella Ehrenbergii, a specimen of which 

 is shown of the natural size at fig. K. This curious species is shown slightly magnified 

 at fig. L, and exhibiting the manner in which the polypes protrude from their cells ; and 

 at fig. M the head and tentacular plume of a single polype is delineated, so as to show 

 its peculiar form has lost the horseshoe outline ana assumed the funnel-like shape of the 



