Xvi lNTRODUC*riON. 



As we fhall frequently have Occafion, in the enfuing 

 Work, to make Ufe of the Term Polype, it will be necef- 

 fary to give the Reader, who may be unacquainted with 

 thefe Subjecls, fome Idea of it ; which, perhaps, may be 

 done the moft fatisfadorily, by defcribing the Frefh-water 

 Polype, whofe extraordinary Properties have been fo fully 

 enquired into by the ingenious Mr. Trembky^ F. R. S. 



In Plate XXVIII. at Fig. C, is exhibited a long-armed 

 Fredi water Polype of this Author: From this Reprefenta- 

 tion the Reader will eaflly know what is intended, when we 

 fpeak of the Marine Polype, its Arms, Claws, ^c. 



This Animal then is, firft, of a Worm-fliaped Figure, and 

 of the fame Kind of tender Subftance with the Horns of the 

 common Snail : It adheres by one End, like a Sucker, to 

 Water-plants and other Subftances. The other End, which 

 is the Head, is furrounded by many Arms or Feeders, placed 

 like Rays round a Centre ; this Centre is its Mouth \ and 

 with thefe tender Arms, which are capable of great Exten- 

 fion, particularly in this Species, it felzes minute Worms, 

 and various Kinds of Water-Infefts, and brings them to its 

 Mouth ; and often fwallows Bodies larger than itfelf ; hav- 

 inof a furprizing Property of extending its Mouth wider, in 

 proportion, than any other Animal, After its Food is di- 

 o-efled in its Stomach, it returns the Remains of the Animals 

 it feeds on through its Mouth again, having no other ob- 

 lervablc Emundtory. 



In a fev/ Days there appear fmall Knobs, or PapiUcBj on 

 its Sides : As thefe increafe in Length, litde Fibres are fcen 

 riiina out ot the Circumlerence of their Heads, as in the Pa- 

 rent Animal, which Fibres, they foon begin to ufe, for the 

 Purpofe of procuring NouriiEment, &'c. When thefe are 



arrived 



