CLASSIFICATION. 105 



Family III. ARGONAUTID^E. 



ARGONAUTA. Characters those of the family. Third right arm hec- 

 tocotylized. 



Family IV. LOLIGINIDvE. 



LOLIGO. Body long, with posterior rhombic fins united behind ; mantle 

 supported by a cervical ridge and by cup-like cartilages on the base of 

 the funnel or siphon ; siphon valved, attached by bands to the head ; 

 arms with two rows of suckers provided with horny, dentated rings ; 

 tentacular arms with four rows of suckers on their clubs. Fourth left 

 arm hectocotylized at its extremity. Gladius feather-like, its shaft 

 keeled on the ventral side. 



LOLIOLUS. Body rather long, with posterior round fins united behind ; 

 siphon not attached to the head. Fourth left arm hectocotylized in its 

 entire length. Gladius feather-like, broad. Otherwise as in Loligo . 



SEPIOTEUTHIS. Body rather long or oval, with small lateral fins extending 



its entire length ; siphon attached to the head by muscular bands ; 



buccal skin, with seven projections covered with suckers ; a strong 



wrinkle behind the eyes. Fourth left arm hectocotylized at its 



extremity. Otherwise like Loligo. 

 TEUTHOPSIS. (Fossil only.) Pen or gladius dilated and spatulate 



behind, its wings curved towards the ventral side somewhat spoon-like. 

 LEPTOTEUTHIS. (Fossil only.) Shaft of the pen enlarging from a point to 



a broad blade in front, with long lateral wings starting from the 



posterior pointed end. 



BELEMNOSEPIA. (Fossil only.) Like Leptoteuthis and perhaps not 

 separable from it. The shaft is more triangular, and the lateral wings 

 broader, with more rounded outlines. 



BELOTEUTHIS. (Fossil only.) Shaft lozenge-shaped, pointed at each end, 

 with posterior lateral wings. 



PHYLLOTEUTHIS. (Fossil only.) Gladius thin, subovate, slightly con- 

 cave below, and convex above. From behind the middle it narrows 

 towards the front, the outline of the lateral margins being convex, 

 while the posterior end is more or less obtusely angular.* 



Family V. SEPIOLID^E. 



SEPIOLA. Body short, purse-like, mantle united to the head cervically, 

 and ventrally supported by a ridge fitting a groove on the funnel ; arms 

 with two or eight rows of pedimculated suckers, the rings of which are 

 not toothed, and eight rows of very small ones on the tentacular clubs. 



*Belemno sepia, Beloteuihis, LeptoteutJiu and Phylloteuthis are very closely 

 related ; it is doubtful whether they should be separated. 

 14 



