lANTHINA. 129 



foot of the animal secretes a kind of mucus^ which is capable 

 of being blown out into a large and compact float of well- 

 connected air-vessels, which, lying on the surface, sustains 

 the slight weight of the animal and sliell just underneath. 

 In the breeding season, the float of the female increases 

 greatly in extent; and the eggs, put forth one by one, ascend 

 to the float above, where each is hung up in a little bag. 

 The little bags near the furthest end of the float are gene- 

 rally found empty, the young ones having gone off to make 

 floats of their own ; those in the centre have the little crea- 

 tures with their thin shells formed ; and those nearest the 

 'animal hold the recently-deposited eggs. 



As the young ones, fully formed, are released from their 

 little cells, they slide up to the top of the parent's float, and 

 thus gaining the surface of the water are soon in a state to 

 assert independence, and float about with their own apparatus 

 complete. 



The lanthinm have a large head, with two tentacula and 

 two short peduncles "in the place where the eyes ought 

 to grow,^" but no appearance of eyes; the breathing appara- 

 tus consists of two plumes; and the foot (so called) is short, 

 secreting the cartilaginous sjjume which forms the float. 



The shell is well known as one of the prettiest of our spe- 



K 



