CA\ADIAX FIfiHERIES EXrEDITlOy, 191>,-1') 



471 



(/() Pterosagilla draco (Xrohn). 



" Acadia." 



Station Xo. 



Hour. 



Depth 



(metres). 



Depth of Haul (metres) 



Length (mm.). 



XuinlxT. 



41 



44 



G a.m 



9 p. Ill 



360 



over 1,000 



over 1,000 



200-0 (V.). 



100-0 (V.). 



(T.). 



270-0 (V.) 



(T.). 



32.S-0 (V.). 



5.5-0 (V.). 



c. 20-10 (T.). 



.5-9 • .5 



Only six specimens were obtained, four of which were in the surface, haul at 

 station 44. Its distribution is shown by the horizontal interrupted lines in fig. 1. It 

 is a tropical surface form. Bigelow obtained it iu July-August, 1913, at his outermost 

 southern stations south of cape Cod. It is noteworthy that it occurred at three of 

 the five stations at which Sagitta enflata was found, and that four of the six specimens 

 came from the onlj^ station where 'S'. enflata was abundant. Fowler notices this agree- 

 ment in the general distribution of the two species (1906, p. 76). 



Fowler gives its most northerly record as 41° 36' N, 56° 18' W. (Strodtmann). 

 Its occurrence at Acadia station 75 (43° 30' N., 56° 43' W.) extends its known northern 

 limit. These two tropical species (for both of which new northerly records are now 

 given and for our waters, their previous northerly records having also been from our 

 waters) come much farther north on this side of the Atlantic than on the European 

 side, where they only reach the latitude of the Mediterranean, thus harmonizing in 

 a general way with the distribution of salinities and temperatures (see Hellaud-IIau- 

 sen in Murray and Hjort, 1912, pp. 227 and 297). Strodtmann, who studied the 

 Chaetognaths obtained by the Plankton-Expedition in the North Atlantic, which 

 included a series of stations both north and south of the Newfoundland banks, con- 

 siders that these two species characterize the true region of the Gulf Stream (1892, 

 p. 369) as opposed to the Labrador current and the northeastern branch of the Gulf 

 Stream. 



Their distribution indicates that the surface water of the Gulf Stream presses 

 in much nearer the continental shelf at the lower (southern) end of our range than 

 elsewhere. 



