of British Mollusca. All 



are transformed into semielliptical vertical plates, which have 

 the faces turned backwards and their summits bent over in 

 that direction ; the corresponding peduncles of the inner row 

 are at first in the form of depressed simple tubercles, but quite 

 at the extremity they also become flattened and closely corre- 

 spond with those of the outer row opposite to them *. 



Subgenus 3. Todaeodes, Steenstrup. 



Tentacular arms having their stems furnished with suckers 

 some way down. Tentacular clubs not furnished at their 

 base with simple suckers and fixing-cushions for their mutual 

 adhesion ; suckers arranged in only four rows quite to the 

 extremity. Lateral arms not having a membranous crest. 

 Siphonal reception-groove with small longitudinal grooves at 

 the anterior end. 



13. Ommastrephes sagittatus (Lamarck). 



Ommastrephes todarus, Forbes and Hanlev, Hist. Brit. Moll. iv. (1853), 

 p. 233, pi. ERR. fig. 2 ; Jeffreys, B. C. iv. (1869), p. 128. 



Todarodes sagittatus, Steenstrup, Ommat. Bkelisp. (1880), pp. 82, 90, 

 &c. ; Hoyle, Report 'Challenger' Cephalopoda, 1886, p. 34. 



(Non Ommastrephes sagittatus, d'Orb.) 



Shetland (Pearceyl), St. Andrews (M'lntoshl), Firth of 

 Forth (Forbes), Durham coast (A. M. N.). 



It has a range coextensive with Europe from the Mediter- 

 ranean to Finmark, Faroe, and Iceland. 



The following is G. O. Sars's description of the radula of 

 this species : — "Lamella? radula? in series 7 dispositas, medianas 

 et laterales tricuspidatse, cuspide centrali majore et longe pro- 

 tracta ; uncini interiores basi intus acute producta, exteriores 

 simplices, falciformes ; lamina? limbales distinctse, minima?, 

 quadrangulares. Formula radula? 1 — 2 — 1.1.1 — 2 — 1." 

 (Sars, 1. c. pi. xvii. fig. 1.) 



* Verrill has described the hectocotylization of the nearly allied Ameri- 

 can species Ommastrephes (Illex) illecebrosus (Lesueur). In the ventral 

 arm of that species the suckers, especially of the outer row for some dis- 

 tance from the extremity, have their pedicels larger and longer, with 

 swollen bases ; then the suckers themselves gradually become smaller, till 

 they nearly or quite disappear, and then close to the tip they may again 

 become normal. Steenstrup testifies to hectocotylization of the same 

 arm in Todarodes and Dosidicus, and in Ommastrephes (restricted). 



