254 Lamarck's Genera of Shells. 



small size. Only one species, Loligopsis Peronii, is known. Of the 

 octopus, Lamarck describes four species. 

 3. Loligo*. 



Body fleshy, contained in an elongated cylindrical sac ; sac 

 pointed at the base, and alate at the lower part. An elongated, 

 thin, transparent, horny lamina, enclosed in the interior of the body, 

 near the back. Mouth terminal, furnished with strong horny man- 

 dibles, like a parrot's bill, and surrounded by ten arms ; arms fur- 

 nished with suckers, with circular, cartilaginous rings, with simple 

 edges ; two of the arms longer than the rest, and pedunculated. 



The loligo is distinguished from the sepia, by its sac being nar- 

 rower, and furnished with the membranes for swimming at the 

 posterior part only ; whereas that of the sepia, which is very much 

 broader, has a narrow ala, or fin, on each side, extending from the 

 upper margin to the base of the sac. A still more striking dif- 

 ference between the two genera, is derived from the sword, or sim- 

 ple, feather-shaped, horny, transparent, dorsal lamina, belonging 

 to the loligo, which, in every respect, is wholly unlike the lamellar, 

 spongy bone of the sepia. 



The internal organization of the two animals is very similar ; 

 each secretes a black liquor, which it can eject at pleasure, and 

 probably on similar occasions. The loligines swim at freedom in 

 the sea, and prey on crabs and other marine animals. They de- 

 posit their eggs in clusters, like a bunch of grapes, all being 

 attached to a common centre, and forming an orbicular mass. 



Type. Loligo vulgaris]'. (Sepia loligo. Linn.) 



Alae semirhomboidal, separate to the extremity of the tail ; 

 border of the sac trilobate ; dorsal lamina contracted anteriorly. 

 European Seas. PI. vi. Fig. 237. 



4. Sepia J. 



Body fleshy, depressed, contained in a sac; sac obtuse posteri- 

 orly, and bordered on each side, through its whole length, by a 



* Original Latia name for a species of cuttle fish. 

 f Common. 



j From sepio, to cover, or conceal, because it conceals itself, when pursued, 

 by the ejected inky fluid. 



