gallery.] natural history. 145 
The family of Cymodoceidce have two wings on each 
side, placed in the space that separates the body into two 
parts. 
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 are the chief 
food of the whales. 
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 Ocythoce , w r hich have the ends of the two 
dorsal arms webbed, take possession of the Argonaut s 
shell, when they are about to lay their eggs. The Philo- 
nexi f which have no eyelids and free arms, live on the 
ocean, while the Octopodes and Eledonce , which live on 
the coast, have distinct eyelids. 
The family of Cuttle-fish ( Sepiadce ) 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. 
H 
