526 ON THE PLANKTON OF THE FAEKOE CHANNEL. [May 18, 



those of T. riisei, the shape of the fin is markedly that of T. beJinii • 

 this is well brought out by Hoyle's figure, which shows a distinctly 

 rhomboid fin. 



A specimen of T. hehnii was described by Weiss ', which agrees 

 almost exactly with the diagnostic characters given above for that 

 species. 



The following table exhibits the dimensions of my specimens, 

 the ' Knight Errant ' specimen described by Hoyle, and the 

 Messina specimen described by Weiss, expressed in percentages of 

 mantle length : — 



' Research.' ' Knight Errant.' ' Messina. 



So far as this goes it is fairly obvious that the ' Knight Errant ' 

 and ' Research ' species are the same, and different from the 

 Messina species ; the dimensions further point to an accurate 

 determination by Hoyle and Weiss of their respective species. 



I have therefore assigned my specimen to T. riisei, although 

 the shape of the tail-fin is distinctly that of the other species. 



Dimensions in millimetres : — end of body to margin of mantle, 

 23 ; breadth of body, 9 ; length of fin, 8 ; breadth of conjoint fins, 

 13; arm i, 5 ; arm ii, 13; arm iii, 11 ; arm iv, 8 ; tentacle, 21. 



The animal was of an absolutely glass-like transparence, except 

 for the two staring black eyes and a black mass posteriorly (? ink- 

 sac). When it had been killed, scattered chromatophores became 

 more obvious, notably four, symmetrically placed on the dorsal 

 surface of the head, and a line of smaller ones along the median 

 dorsal line of the mantle ; they were of a deep claret -colour. 



As Hoyle ^ pointed out, and was corroborated by Jatta ^, TracTie- 

 loieuthis is a member of the subfamily Ommastrepliini ; the latter 

 author refuses, however, to accept the suggested identification of 

 TracheloteutJiis with VerriUiola-= Entomopsis, as the four species 

 described under these two genera are members of the Taonoteuthi. 



Distribution : — 



(1) Eaeroe Channel— 60° 29' N., 8^^ 19' W., surface ('Knight 

 Errant ')• 



(2) Eaeroe Channel— 60° 2' N., 5° 49' W., 100 to fathoms 

 (•' Research '). 



(3) Atlantic, Mediterranean (Steenstrup). 



^ Quart. Journ. Micr. Sci. xxix. pp. 75-96, pis. viii.-x. 



^ Loc. cit. 



^ Fauna e Flora Golf. Neapel,— I Cefalopodi (Sistematica), p. 112. 



