78 TURBELLARIA. 



eye-specks, and assume the form of the parent 

 animal. An interesting discovery has been made 

 by Professor Agassiz, that the animals which, under 

 the names of Kolpoda and Paramcecium^ had been 

 described as genera of INFUSORIA, are really the 

 larvae of Planarice; and probably other Infusorial 

 forms may ultimately prove to be the earlier stages 



of TURBELLARIA. 



Localities. A large number of the genera are 

 confined to fresh waters. Such as are marine are 

 mostly found between tide-marks, crawling about 

 sea-weeds, or clinging to the under-surfaces of 

 stones. The Cestoidea often hide themselves in 

 narrow crevices and hollows of rocks ; and a very 

 productive mode of searching for these, as well as 

 many others of that extensive Class that the Shet- 

 land fishermen so expressively term " pushen," is 

 to break up the flat friable ledges of sandstone or 

 conglomerate, between which the sea has worked 

 innumerable cracks, sand-layers and caverns ; which 

 are found well peopled with strange and uncouth 

 creatures. The curious genus Serpentaria, the giant 

 of the tribe, was obtained by Mr. Goodsir from 

 deep water. 



Authorities. I have used for the arrangement 

 of the Class, Oersted's " Plattwurmer," an admir- 

 able little monograph ; and for the British species 

 I am chiefly indebted to Dr. Johnston's " Index to 

 the British Annelides," to Mr. Thompson's papers 

 in the " Annals of Nat. Hist.," and my own per- 

 sonal observations. 



TURBELLARIA. 



Bilateral animals, of soft fleshy substance, covered 

 with vibrating cilia, with the body more or less 



