30 



RIO DE JANEIRO. Mslj — Junc^ 1832. 



existence of a division of the genus Planaria^ which inhabits 

 the dry land^ interested me much. These animals are of so 

 simple a structure, that Cuvier has arranged them with the 

 intestinal worms, though never found within the bodies of 

 other animals. Numerous species inhabit both salt and 

 fresh water ; but those to which I allude were found beneath 

 logs of rotten wood, even in the drier parts of the forest. 

 In general form they resemble little slugs, but are very much 

 narrower in proportion. I met with one specimen no less 

 than five inches long. The lower surface, by which they 

 crawl, is flat, the upper being convex : in this latter respect 

 the terrestrial species all differ from the depressed forms of 

 the aquatic. Their structure is very simple. Near the 

 middle of the under surface, there are two small transverse 

 slits, from the anterior one of which a funnel-shaped organ, 

 or cup, can be protruded. This seems to act as the 

 mouth. It is soft, highly irritable, and capable of various 

 movements ; when drawn within the body it is generally 

 folded up like the bud of a plant. From the central position 

 of the orifice, the animal has its mouth in the middle of what 

 would commonly be called its stomach ! For some time 

 after the rest of the animal has become dead from the eff*ects 

 of salt water, or other cause, this organ still retains its vitality. 

 The body is soft and parenchymatous ; in the central part a 

 transparent space, with lateral ramifications, appears to act as 

 a system of circulation. Minute, black, eye-like specks are 

 scattered round the margin of the crawling surface, and 

 more abundantly close to the anterior extremity, which is 

 constantly used as a feeler. In a marine species, I ex- 

 tracted from the central parts of the body vast numbers of 

 little spherical eggs ; they were .006 of an inch in diame- 

 ter, and contained a central opake mass or yolk. 



The terrestrial Planarise, of which I have found no less 

 than eight species, occur from within the tropic to lat. 47*^ 

 south, and are common to South America, New Zealand, 

 Van Diemen's Land, and Mauritius. Some of the species 



