RESEARCHES IN HELMINTHOLOGY AND PARASITOLOGY 1 1 



The general sensibility of P/iagocata is very considerable, that is, 

 it contracts with great readiness from the slightest disturbance. The 

 contraction has much the appearance of being involuntary and is 

 ver}" like that of the medusae. When an individual is irritated at 

 any point, contraction commences there, and thence rapidly extends 

 throughout the animal, and the only appearance of volition is in the 

 effort to escape, but if the touch be too rude, apparently involuntary 

 contraction takes place suddenly and appears to destroy all power of 

 volition for the moment ; the animal, how^ever, soon revives from this 

 state and glides off with its accustomed speed. 



Some experiments which I performed upon Phagocala confirm the 

 statement that the Planarise are capable of repairing injuries. When 

 an individual is cut into two, both parts after a time become distinct 

 and perfect animals. Division carried to a greater extent in some 

 instances results in as many perfect animals as there are parts, but 

 generally I have found that when cut into more than three or four 

 pieces, the intermediate pieces are apt to die, and sometimes the 

 extremities do not survive. 



I exhibit a drawing of Phagocata gracilis, from Prof. S. S. Halde- 

 man. 



A drawing of two individuals feeding upon a piece of lyumbricus. 



Do., representing the ventral surface with the proboscides pro- 

 truded. 



Do. , representing the digestive and generative apparatus. 



Do., representing five of the proboscides highly magnified. 



[August, 1847. No. 21. See Bibliography.] 



DESCRIPTIONS OF TWO NEW SPECIES OF PLANARIA. 



Planaria macula ta. — Superiorly convex, faintly blackish or brown- 

 ish with irregular colourless maculae; inferiorly flat, colourless; 

 anteriorly trapezoidal ; posteriorly spatulate or oval ; eyes two, an- 

 terior, proximate, composed of a large semi-transparent mass with 

 a reniform mass of pigmentum nigrum at the postero-internal part ; 

 oral aperture ventral, one-third the length of the body from the pos- 

 terior extremity ; proboscis large and cylindrical. Length 2]4^ lines ; 

 breadth ^2 line. Found in moderate abundance, in the ditches below 

 the city, creeping upon the submerged stems of aquatic plants. 



Subgenus. Prosfonia, Duges. Mouth anterior and terminal. 



Pfostoma luarginatiDu. — Blackish, narrow lanceolate, anteriorly 

 truncate ; marginate, margin delicately striate ; mouth large ; pro- 



