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



those of T. riisei, the shape of the fin is markedly that of T. behnii ; 



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



rhomboid fin. 



A specimen of T. behnii was described by Weiss l , 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. 

 Length of mantle in mm. 28 32 21 



Breadth of mantle '38 -25 



Length of fin -34 -40 -28 



Breadth of fins -56 -59 '38 



Length of arm 1 -21 -24 -14 



2 -56 -56 -33 



3 -47 -46 -28 



4 -34 -40 -19 



Length of tentacle -91 1-00 -61 



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

 and 'Besearch' 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 hi, 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 (? iiik- 

 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 2 pointed out, and was corroborated by Jatta 3 , Trache- 

 loteuthis is a member of the subfamily Ommastrephini ; the latter 

 author refuses, however, to accept the suggested identification of 

 Tracheloteuthis with VerrilliolaEntomopsis, as the four species 

 described under these two genera are members of the Taonoteuthi. 



Distribution : 



(1) Faeroe Channel 60 29' N., 8 19' W., surface ('Knight 

 Errant ') 



(2) Faeroe Channel 60 2' N., 5 49' W., 100 to fathoms 

 (' Besearch '). 



(3) Atlantic, Mediterranean (Sttenstrup). 



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



2 Loc. cit. 



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



