PLANARIA. 123 



all were nearly of the same size, the conjecture was probably erroneous ; 

 therefore, until its proper place be ascertained, let it be named, provi- 

 sionally, Planoidcs fusca. 



Length a line and a half; breadth and thickness nearly half the 

 length. Body compact, solid ; the anterior extremity divided horizon- 

 tally into two lips, wherein is perhaps the mouth. This extremity is 

 fashioned somewhat as a scoop by the fold of a membranaceous edge, ap- 

 parently reflected on the back. A dark red internal organ is situate 

 towards the centre of the body. Neither eyes nor marginal specks have 

 been discovered, nor any prominent parts of external organization. 

 Colour brownish, speckled. Motion smooth and gliding. 



This animal has always a tendency to crawl upwards, whence it is 

 allured, by the smoothness of the glass, to quite the water, and is lost, 

 which may be prevented by filling a small vessel to the brim, and cover- 

 ing it with an inverted, loaded, watch-glass. Marine. 



PLATE XVI. 



FIG. 35. Planoides fusca. 

 36. The same, enlarged. 



Notwithstanding the tender and delicate consistency of the Plana- 

 rian race, and their liability to perish, they seem to survive longer with 

 care than might be anticipated. Some of the Planaria Edinensis, taken 

 in October 1813, exhibited internal ova a year later, and still survived 

 in March 1815. Also some of the same colony, or their progeny, were 

 found alive during September 1819, in the vessel originally appropriated 

 for their reception, five years earlier. 



The preceding list of species does not by any means exhaust the 

 whole which are to be found in the Scotish waters. Besides several of 

 more ample dimensions, many very minute specimens appear transiently, 

 especially during the summer months, among the water taken from ponds, 

 lakes, or marshes. When this has been sometime introduced into vessels, 



