CANADIAy FISHEnir:S expedition', lOL'rlo 



423 



(a) Sagitta hexaptera d'Orbifrny. 



1911. Eitter-Zahony, p. 12. 

 The specimens varied in size from ll-50mm. in length. 



DISTRIBUTIOX. 

 r. G. S. "Acadia." 



Station No. 



16 



17 



44 



56 



74 



75 



Depth (metres). 



over 2,000 



over 2,000 



over 1,000 



over 1.000 



over 1,000 



over 1,000 



Depth of Haul (metres). 



Length fmm.). 



200- (V.). 



(T.). 



200- (V.). 



(T.). 



270- (V.). 



(T.). 



375-2.50 (C). 



250- (V.). 



.32.5- (V.). 



55- (V.). 



c. 20- 10 (T.). 



.325- (V.). 



55- (V.). 



c. 20- 10 (T.). 



32 & .50 



13, 21 & 36 



17 & 20 



11 & 12 



30 



Number. 



Vertical. — With one exception this species was obtained only in deep open net 

 hauls, down to 200 metres or over, and did not occur in the shallower hauls (55 

 metres up). The exception was in a tow hau Itaken about 20 metres below the surface 

 at station 74. The two individuals obtained were the smallest taken (11 and 12mm.). 



The small number of individuals found is quite inadequate for determining the 

 distribution, but the hauls made at stations where the species was found show its 

 absence below 250 metres, its rarity above 55 metres (and then only small individuals), 

 and its uniform presence in hauls made through intermediate depths. This agrees 

 with the finding of Michael (1913, p. 34) who suggests its maximum abundance as 

 existing between 50 and 100 fathoms, based upon twenty-eight specimens taken in 

 fourteen hauls. The presence of two small individuals near the surface in station 74 

 on the edge of the Gulf Stream, is explained by the fact that in warm waters this 

 species occurs quite to the surface in its younger stages. 



Horizontal. — Sagitta hexaptera is a cosmopolitan oceanic form occurring in 

 tropical regions, but large individuals have been found far into the polar regions. 



It was found only in the outermost warm water stations of the Acadia's cruises, 

 and it occurred in every one. As it is a form characteristic of intermediate depths, 

 from 100 to 200 metres, its distribution is an indication of the extent to whicli this 

 intermediate water has pressed in toward our shores from the open Atlantic. Tlie 

 imier limit of its distribution would appear to be well outside the continental shelf, 

 perhaps sixty or more miles in May and June, and rather closer, from twenty to forty 

 miles, in July and August. Its distribution (shown for July-August by the vertical 



