PLUMATELLA JUGALIS. 109 



P. jtigalis is a small species and occurs, rather abundantly in the sluggish waters of the 

 Chelmer Canal, attached to the petioles and under surface of the leaves of Nymphcea alba. 

 It is throughout closely adherent to the surface on which it grows, and is very remarkable 

 by its naode of development in two distinct groups of branches, which arc united to one 

 another by a simple connecting tube, from which they extend in two opposite directions. 

 The ectocyst is brown, becoming lighter towards the extremities of the branches, and finally 

 extending as a delicate transparent and colourless membrane to the margin of the orifice ; 

 this transparent portion being, as in other furrowed species, withdrawn into the more opaque 

 portion of the tube during extreme retraction. Most of the branches are intersected near 

 their origin by very distinct septa, which are visible through the walls of the tube. I could 

 find no statoblasts in any of the specimens I examined. 



In its peculiar mode of development in two groups of tubes, P. _;e<^«/2s presents a striking 

 resemblance to Alcyondla flabelhim ; from the latter animal, however, it is at once distinguished 

 by its narrow, widely diverging branches never contracting the slightest adhesion to one 

 another. 



I have as yet met with this species in but one locality, though its striking physiognomy 

 could scarcely allow of its being overlooked. 



The Plumatella nitida, Leidy ('Proc. Acad. Nat. Sci. of Philadelphia,' vol. v, p. 321), 

 I cannot think entitled to rank as a distinct species. With the exception of the number of 

 tentacula, which are described as being only forty-two, there is no character in which P. 

 nitida does not entirely agree with P. repens, and this character by itself can scarcely be con- 

 sidered of suiScient importance to separate the two forms. 



