212 PECTINIBRANCHIATA.—CALYPTREADAL 
that the young Calyptree are developed under 
this sort of maternal roof, and do not quit it until 
they are in a condition to affix themselves, and 
are provided with a shell sufficiently hard to pro- 
tect their own bodies.” * 
Our other native genus of this family is said to 
manifest an instinct similar to this. 
GENUS PILEOPSIS. 
The Fools-cap Limpets, as the mollusks of this 
genus are called, have the shell shaped like a 
somewhat high cone, with the summit a little pro- 
duced, and turned over backwards. The surface 
is commonly marked with lines (ste), and covered. 
with a horny skin, which is sometimes invested 
with a short velvety down. The interior has no 
plate or partition of any kind. The place of the 
attachment of the muscle is marked by a horse- 
shoe impression. ‘The animal has been already 
described. 
The only British species is commonly known by 
the appellation of Torbay Bonnet (Pileopsis Hun- 
garwus) ; it also bears the names of Fools-cap 
Limpet, Cap of Liberty, and Hungarian Bonnet, 
all of which designations, as well as both of its 
scientific ones, have an obvious reference to its 
form. It isa rather large shell, being frequently 
more than an inch and a half in diameter, and an 
inch in height. Its substance is rather thin, though 
strong, and somewhat translucent; its colour is a 
delicate pink, or flesh-white, though this is con- 
cealed, especially around the lower part, by an 
olive-coloured skin, covered with shaggy down. 
* Litt. de la France, i, 138. 
