CAXADIAX FISHERIES EXPEDITION, 1914-lo 431 



extremely rare) for the San Diego region. Fowler (1896, p. 9f>2 as S. whartonx) in 

 his investigations of the Faeroe channel found it only on one occasion above 100 

 fathoms, and Ritter-Zahony for the coasts of Ireland found it regularly only below 

 100 fathoms. 



In the Gulf Stream stations of the second cruise a gradation in depth according 

 to size is evident. At the southernmost station (station 44), the haul from 270 metres 

 up yielded no specimen longer than 19mm. At station 56, the next station north, the 

 haul from 250 metres up gave specimenes up to 21mm., and the haul from 375 to 250 

 metres, specimens up to 25 ( ?) mm. The northern Gulf Stream stations (stations 74 

 and 75) from a depth of 325 metres to the surface gave specimens up to 16 mm. and 

 24mm. respectively. The boreal stations yielded much larger specimens from similar 

 depths (e.g. up to 25, 28, 42, 55, 40, 36, and 40mm. at stations 54, 55, 57- 70, 72, 76, 

 and 79 respectively). Therefore, as we pass into warmer water the larger specimens go 

 decider and deeper down and only the smallest specimens occur near the upper limit of 

 distribution. It is worthy of note that at the Gulf Stream stations of the second cruise 

 (stations 44, 56, 74 and 75) in eaeli of the hauls, the average size of S. maxima (the 

 larger species) was less than the average size of S. lyra (the smaller species). This 

 seems to indicate that S. lyra attains its maturity and perhaps also its maximum abun- 

 dance in the upper part of the mesoplankton- and *S^. maa:ima its maturity and maximum 

 abundance in the lower part of the mesoplankton. These two closely related species, 

 though having to a great extent a coincident horizontal distribution would be rather 

 sharply separated in their vertical distribution, as Michael (1913) has shown to be the 

 case for other couplets of species in this group. Data as to the lower limit of distri- 

 bution S. lyra are lacking, although Ritter-Zahony (1910) appears to have obtained it 

 in quantity below 700 fathoms. 



Horizontal. — This species is cosmopolitan, extending to the far north in the Atlantic, 

 so that it may be considered a cold-water species, distributed in all oceans in the depths. 

 In our waters in the depths that we have examined (down to from 200 to 300 metres) 

 it occurs in greatest abundance outside the continental shelf and inside the outermost 

 stations, that is, inside the Gulf Stream. Little can be stated as to its distribution 

 during the first cruise of the Acadia, owing to the fact that only three deep hauls 

 were made. At station 17 an extraordinary number were obtained, 12S in the one 

 open-net haul from 200 metres to the surface. Larger individuals were obtained at the 

 innermost of the thre stations, 30 and 32toim. at stations 17 and 14, respectively, as 

 opposed to 25mm. at station 16. The records indicate that it was present in maximum 

 abundance between station 16 and the Newfoundland banks, and decreased in abund- 

 ance toward the west and south. Its distribution in July-August is shown in fig. 3. 

 It occurred in moderate abundance at the outermost stations (7, 5, 8 and 4 specimens 

 at stations 75, 74, 56 and 44- respectively). At the remaining- stations outside the con- 

 tinental shelf, it occurred in maximum abundance at the northeast, and decreased in 

 abundance with almost perfect regularity, passing to the southwest, until it disappeared 

 altogether (14, 14, 8, 10, 7, 6, 4, 1, 0. and specimens at station 79, 76, 72, 70, 

 57, 55, 54, 46, 45, 42 and 41, respectively) considering in each case only the deep open- 

 net haul. It also occurred in fair abundance up the gully leading to the Gulf of St. 

 Lawrence. In the gully it was present in greater amount on the north side, the num- 

 bers obtained in the deep vertical hauls being 6, 5 and 2 specimens, respectively, at 

 stations 85, 86 and 87. Inside the Gulf of St. Lawrence, on the cruises of the Princess, 

 it was not found, perhaps because the hauls were not deep enough (not over 130 

 metres). The only other place where it was found was at station 48 in the deep water 

 inside the outer banks off Halifax, where a solitary specimen was obtained. Its dis- 

 tribution (fig. 3) suggests (1) that this species belongs typically to the deep boreal 

 water that is found against the side of the continent; (2) that this water disappears 

 as we pass southwest along the continent, doubtless seeking a lower level, unexplored 

 by our nets; (3) that some of it passes up over the banks south of Sable island to mix 



