NATURAL HISTORY. 
87 
GALLERY.] 
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 fur¬ 
nished 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 only two gills. They swim tail foremost, 
or walk and run on their heads with the end of their body on high. 
The family of Sea-spiders ( Octopodid^e) have a purse-like body, 
without any fins, only eight sessile arms, and no shell. The Ocythoce , 
which 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 
Philonexi, 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 ( Sepiad^:) 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 fur¬ 
nished with suckers at the end, which are not developed until some 
time after they are hatched. The greater part of the genera have a 
cartilaginous, and a few, as Sepia , a calcareous internal dorsal plate. 
The fin is generally placed on the hinder part of the body, being rounded 
in Sepiola and Rossia; angular, forming together a lozenge-shape, in 
Omastrephis, and half ovate in Loiigo; and in Sepioteuthis and Sepia 
they occupy the greater part of the length of the side. The disks or 
suckers on the arms are supported by a circular homy ring, which is 
usually toothed on the outer edge, in Onychoteuthis the upper edge of 
those on the long arms, and in Enoploteuthis of all the arms, are pro¬ 
duced into a sharp claw-like hook, making a dangerous weapon. 
The fossils called Beloptera are similar to the conical process found 
on the top of the sepia bone; but instead of being horny, as in that 
genus, they are distinctly shelly, and have a deeper cavity. 
The family of Belemnites ( Belemnithle) are evidently very nearly 
allied to the Cuttle-fish, and have a similar internal dorsal bone; the 
conical substance so commonly found fossil being only a greater 
developement of the apical process, which is found on the end of the 
bone of the common cuttle-fish; the Belemnites , however, differ 
from the cuttle-fish in the cavity of the shell, which is produced into 
this conical process, being furnished with cross septa having a distinct 
syphon, like the JVautilidce, and in this greatly developed apical process 
being strengthened as the animal enlarges in size, by the addition of 
coats of shelly matter being deposited on its outer side, which is 
evidently secreted by the inner surface of the cavity of the mantles in 
which it is inclosed. The fact of their being so covered is proved by their 
being united together again by an external covering when they have been 
accidentally broken during the growth of the animal, as can be seen by 
a longitudinal section of any of the distorted or odd shaped specimens, 
and the matter deposited on the outer surface assumes the prismatic 
crystalline texture, as is the case with the similar secretions placed in 
