PLANARIA. 110 



when falling through the water. Dwells on the F 'lustra hispida, where 

 it is not rare, in July and August. Marine. 



PLATE XVI. 



FIG. 32. Planaria flustrce, enlarged. 



e. PLANARIA VORAX. Plate XVI. Figs. 33, 34. 



Length an eighth of an inch, greatest thickness a third of the length. 

 Body round, tapering downwards ; head obtuse, tail acute. No eyes 

 visible. The mouth is apparently in front. The animal feeds readily on 

 fish, and when replete, resembles an inflated vesicle, tapering downwards, 

 the food occupying a capacious ovoidal stomach. 



From one to five ovoidal brown ova are lodged towards the posterior 

 part. But none of those which were produced afforded any progeny. 

 Two continued visible for twenty-four or twenty-five days in a specimen, 

 when it perished accidentally. 



The Planaria wrax dwells in fresh-water marshes, along with the 

 Planaria graminea, which it devours when dead. There is some corre- 

 spondence between the figure and habits of both ; in them the anterior 

 appears greenish. Numbers of each congregate together after a similar 

 fashion, at the bottom of their vessel, where, also, the wrax prefers 

 abiding, amidst mud and decaying vegetables. Bare. 



PLATE XVI. 



FIG. 33. Planaria vorax. 

 34. The same enlarged. 



/. PLANARIA GRAMINEA The Grass Green Planaria. 



Having previously given several illustrations of the history of this 

 species, I shall now restrict myself to a few observations made long after- 

 wards, but for the repetition of which no recent opportunity has oc- 

 curred. 



