L4 
extending its tubular trunk or tongue, and dis- 
charging from its tip a minute drop of gluten, 
which, by the retraction of the same organ, is of 
course formed into asilken filament; and this opera- 
tion being several thousand times repeated, a thick 
and beautiful tuft of silky fibres is composed, by 
the help of which the animal is securely fastened or 
anchored in such places as it finds convenient. The 
Pinna muricata is among the smaller species of this 
genus; measuring about six or eight inches in 
length. In color, as well as in the degree of rough- 
ness of its external surface, it varies considerably. 
It is commonly of a deep brown externally, and of 
a reddish tinge, varied with a degree of pearly lustre 
internally. "The silk or byssus of the Pinnz is of a 
rich golden brown color, and is occasionally manu- 
factured into gloves, &c. by the inhabitants of those 
parts of the Mediterranean coasts where it most 
abounds, viz. on some of the coasts of Italy and 
Sicily. It should be added, that the power of ad- 
hering by means of silken filaments thus drawn from 
the inhabiting animal, is not entirely confined to 
the genus Pinna, but takes place, in a smaller de- 
gree, in some species of Mytilus, | 
