244 Miscellaneous. 



animal, so that when the latter is placed beneath the microscope and 

 slightly compressed, they will be seen pressing upon one another in 

 such a manner, that if one changes its position, it will be instantly 

 occupied by another. Those which are formed last are smallest, but 

 they soon gain their full size. 



When the animal feeds, the whole of them are protruded from the 

 oral orifice, the longest extending out full one-third the length of 

 the body. As they are all convergent to the same orifice, when fully 

 protruded the animal becomes puckered up and increased in breadth 

 at the expense of the length. In this state the anterior extremity is 

 erected and the posterior brought nearly to a right angle with it, so 

 that it looks as if sitting upon its prey apparently unconcerned, with 

 its proboscides, 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 en- 

 tirely 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 forwards or towards the mouth, which they do by contract- 

 ing the stomachal 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 contrac- 

 tion and dilatation of diflferent parts of the same tube, it is thrown 

 backwai'ds and forwards several times, and finally violently expelled 

 at the torn extremity. When they have escaped f'rom 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 phsenomena. In fact, these curious independent move- 

 ments caused me at first to mistake the organs for viviparous young, 

 and it was not until I had frequently observed the animal feeding, 

 and examined its structure 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 ar- 

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

 plied to two semitransparent lines passing along each side of the 

 ventral 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 re- 

 ticulation 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 Planaria the animal is androg)'- 

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

 nerative 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 



