36 LOLTGINID^. 



arms have two rows of cups, the rings provided with a 

 narrow prominent ridge on the centre of the external sur- 

 face ; the tentacular arms are only partly contractile into 

 the sub-ocular cavity, and the siphuncle is attached to the 

 head by a double superior medial band. 



Genus GONATUS, Gray. 



Head separate from the body. Mantle free all round. 

 Fins posterior, dorsal, rhombic. Cups of sessile arms in 

 four rows. Tentacular arms with many rows of small cups, 

 and a single hooked cup at the base. 



Shell as long as the back, pennate, edges thin. 



Ex. G. amoena, Moller, pi. 4, fig. 2. 



In Gonatus the eyes are large, covered by the skin, with 

 a small transparent spot ; the cups on the sessile arms are 

 small, conical, contracted at the top, nearly uniform in size, 

 and in four series ; the club of the tentacular arms is 

 compressed, and finned at the tip. The shell is horny, 

 thin, lanceolate, pennate, narrowed and extended in front : 

 there is one species, G. amwna^ from Greenland. 



Genus LOLIGO, Lamarck. 



Head separate from the body. Mantle free all round. 

 Cups of sessile arms in two rows ; lateral membranes with 

 cups on the angles. Fins posterior, dorsal, rhombic. 



Shell as long as the back, pennate, edges thin. 



Ex. L. magna, Bondeletius, pi. 4, fig. .3. Shell, L. 

 magna, fig. 3, a. 



The rings of the suckers are horny and dentated, and 

 the tentacular club has four rows of cups. The Loligo 

 pursues its prey on the bosom of the ocean, and swims 



