45 8 



VARIATION IN FORM. 



square foot 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 polypes in various stages of protrusion, some being seen withdrawn wholly into their 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. Alcyonella fung6sa. B. Alcyonella fung6sa. X C. Alcyonella fung6sa. X( Tentac l es ' a polypes 

 D. Plumatella repens. E. Plumatella repens. X F. Plumatella repens. (Statoblast. X) 



G. Plumatella repens. (Statoblast, side view. X) H. Frederlcella Sult&na. X 



I. Frederioella Sultana. (Statoblast X) " K. Paludioella. L. Paludicella. X 



M. Paludicella. (Tentacles. X) N. Paludicella. (Tentacles. X) 0. Paludicella. (Tentacle. XX) 



The sign X signifies that the object is magnified. 



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

 sultana ; the former title being given to it in honor 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 protude 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 and assumed the funnel-like shape of the 



