182 LECTURE XL 



of pointed trunk, with which it touches the object 

 it wishes to adhere to, and by retracting it, forms 

 a glutinous thread; and, by the repetition of 

 this motion, forms the whole tuft by which it is 

 fastened. 



The large sea Pinna or Pinna rudis is a cu- 

 rious instance of this. This shell is brown exter- 

 nally, with a slightly iridescent silvery cast with- 

 in ; of a lengthened shape, with a very narrow 

 base, and dilated and rounded towards the extre- 

 mity. It is a frequent inhabitant of the Euro- 

 pean coasts, and in some places, as about the 

 coasts of Sicily and Italy, the silken tufts are often 

 collected, and spun into various articles of dress, 

 as gloves in particular ; the silk requiring no dye, 

 but retaining its native colour, which is an ele- 

 gant, glossy, yellowish brown. Specimens of this 

 kind of silk are generally to be seen in most of our 

 Museums. Neither is this faculty of fastening or 

 anchoring by means of silken fibres confined to 

 the genus Pinna, but takes place, as we have al- 

 ready seen, in the genus Mytilus, and probably in 

 some of the rest. 



I now proceed to the Multivalve Shells, so 

 named, as consisting of several valves or pieces. 



