GALLERY.] NATURAL HISTORY. 149 
The family of Clionidce have only two wings, which are 
said to be covered with a vascular net-work, and serve 
the purpose of gills ; their head is formed of two rounded 
lobes, with small conical tentacles and two fleshy lips; 
their body is oblong depressed; they and the Limacinaz are 
the chief food of the whales, though they are very small. 
The Headwalking Mollusca, or Cephalopoda, have 
a large head armed with strong jaws, like a parrot’s 
beak, furnished with two large eyes, and crowned with 
fleshy tentacles. The head is separated from the oblong 
body by a distinct neck, which has an excretory tube in 
the front of its lower part. Their gills are inclosed in 
the bag-like body. They are all marine, changing the 
colour of their skin with great rapidity; they live on 
marine animals, are voracious and cruel, and some are 
themselves esteemed as food. They are divided into two 
orders. 
The Sepiophora have a naked oblong or conical 
body, often furnished with two longitudinal fins, and they 
have eight or ten fleshy conical tentacles on the head, 
furnished with sucking disks. Their eyes are sessile, 
and they have have only two gills. They swim tail fore¬ 
most, or walk and run on their heads with the end of 
their body on high. 
The family of Sea-spiders ( Octopodidce) have a purse¬ 
like body, without any fins, only eight sessile arms, and 
no shell. The Ocythoee, which have the ends of the two 
dorsal arms webbed, take possession of the Argonauts 
shell, when they are about to lay their eggs. The Philo- 
nexi , which have no eyelids and free arms, live on the 
ocean, while the Octopodes and Eledonee, which live on 
the coast, have distinct eyelids. 
The family of Cuttle-fish ( Sepiadee ) have an elongate 
body with a fin on each side; they have, besides the eight 
arms of the former family, two longer arms, cylindrical at 
the base and enlarged and furnished with suckers at the 
end, which are not developed until some time after they 
are hatched. They have a cartilaginous or calcareous in¬ 
ternal dorsal plate. 
From the imperfect specimens of the animals of the ge¬ 
nus Spirula which have been seen, and from the very 
small size of the terminal chamber, the tenuity of the 
structure, and the colour of the shell, there is every rea- 
