14 



15 



i6 



17 



18 



1 



HOYI.E : BRITISH CEl'HALOrOUA. 203 



C Mantle united with the funnel on either side at 



I its base - - - - Taonius hyperboreus^ 



I Mantle forming a cartilaginous articulation with 



I the base of the siphon on either side - - 13 



r The integument of the head passing continu- 

 ously over the eyes (Zt?//!^^?) - - - \\ 

 The eye lying open in a cavity with free eye-lids - 1 7 



Hinder extremity rounded ; fin more than half 

 the length of the mantle ; size of adult more 

 than 150 mm. in length of mantle - - 15 



Hinder extremity pointed ; fin not exceeding 

 half the length of the mantle, which does not 

 exceed 150 mm.- - - - - 16 



Four subequal rows of suckers on the tentacles ; 

 chromatophores united into elongated patches 

 on the anterior part of the ventral surface of 

 the mantle - - . . Loligo forbesi 



Two rows of large central and two rows of small 

 lateral suckers on the tentacle ; chromato- 

 phores evenly distributed - - Loligo vulgaris 



Mantle terminating posteriorly in a conical apex; 

 suckers of sessile arms with smooth horny 

 ring ; large tentacular suckers with square 

 teeth - - - - Loligo viarmortt 



Mantle terminating posteriorly in a longer or 

 shorter cylindrical process ; suckers of sessile 

 arms with a toothed horny ring ; suckers of 

 tentacles with a smooth ring - - Loligo media 



Mantle connective consisting of a long ridge on 

 either side fitting mto a trough-like groove 

 on either side of the base of the funnel - - 18 



Mantle connective in the shape of an inverted -L 

 fitting into a similarly shaped cartilage at the 

 hd&Q oi\ht.iwx\\MA {OininastrepJiidce) - 19 



Size large, exceeding i"5 metre in length of 



mantle ----- Archikuthus 

 Size small or moderate, not exceeding 50 mm. in 

 y length of mantle- - - Traclieloteuthis"' 



f iVrms of the third pair with a broad membranous 

 19 1 expansion, crossed by parallel ribs; funnel 



-^' groove with folds - - \Sthenoteuthis) 20 



1 Other members of the family Cranchiidai would also come in here. 



2 In some specimens of Loligo media with very elongated caudal extremity, the length of 

 the fin may exceed half that of the mantle. 



3 A species of this genus (7'. 7-iisci Stp.) has been recorded from a loc.ility only a few miles 

 north of the British area as here defined, so that it may reasonably be expected to occur within 

 that area ; for further details see Hoyle, '86, p. 163, Fowler, '97, p. 525, Steenstrup, '98. 



