250 [Aug., 184T. 



boscides, which writhe and twist about as if they were totally distinct 

 organisms. 



If one of these animals be punctured or cut, one or more of the 

 proboscides will be immediately protruded as if they existed under 

 pressure, and will move about in all directions appearing as if entirely 

 without the control of the animal ; or if one of the animals be crushed 

 between two slips of glass so that the proboscides will be torn from 

 their attachment, they move about involuntarily, always in a line for- 

 wards or towards the mouth, which they do by contracting the stom- 

 achal extremity towards the oral, the latter remaining fixed. In this 

 progressive course they constantly contract and dilate ; the mouth 

 opens and any matter in its vicinity rushes in, when it is closed and 

 the matter passes onwards, and by the alternate contraction and dila- 

 tation of different parts of the same tube, it is thrown backwards and 

 forwards several times, and finally violently expelled at the tornax - 

 tremity. When they have escaped from the ruptures of the tegument 

 produced by crushing, or when snipped off with a pair of scissors 

 whilst an animal is feeding, they will present the same curious pheno- 

 mena. In fact these curious independent movements caused me at 

 first to mistake the organs for viviparous young, and it was not untd 

 I had frequently observed the animal feeding, and examined its struc- 

 ture beneath the microscope, after having fed them upon coloured 

 food, that I was convinced of their true nature. 



Excrementitious matter is expelled from the digestive cavity 

 through the same course by which the food enters. 



Circulation. There appears to be nothing peculiar about the 

 arrangement of the blood vessels, if such they be ; the term being ap- 

 plied to two semitransparent lines passingalong each side of the ven- 

 tral surface, and a third along the middle of the dorsal surface, the 

 three freely communicating with each other by transverse lines and 

 numerous smaller branches, the whole forming an extensive reticula- 

 tion upon the surface of the body. At the anterior part of each 

 ventral line, I distinctly observed a dilatation to exist. 



Generative apparatus. As in all Planarim the animal is androgy- 

 nous. The penis is a bulbiform organ placed between the oral and 

 generative orifice with its point directed towards the latter. The 

 point is straight, or contorted; the bulbous portion is also changeable, 

 sometimes elongated, at others flattened or increased in breadth at 

 the expense of the length. The bulb shows through the thin integu- 

 ment, and without close examination may be taken for a third orifice. 

 The penis is perforate, and has a dilated cavity within the bulb. Im- 

 mediately above the penis I indistinctly observed a somewhat lobated 

 organ, which appeared to join the penis at its base by a narrow por- 



