Xo. 553] DISTRIBUTION OF THE CHJETOGNATHA 25 



S. BIPUNCTATA AND S. DECIPIENS 



8. bipunctata is a eurythermal, euryhyaline and cos- 

 mopolitan species recorded from the epiplankton of the 

 arctic, sub-arctic, north temperate, tropical and south 

 temperate Atlantic Ocean, the south temperate and trop- 

 ical Indo-Australian Ocean, and the north temperate 

 Pacific Ocean, as well as from the mesoplankton of the 

 north temperate and tropical Atlantic. Its northern 

 limit is 74° N. and its southern 28° S. The highest tem- 

 perature recorded in connection with its capture is 

 33°.6 C.j while the lowest is 0°.2 C. S. decipiens, on the 

 other hand, is mesoplanktonic. Both were taken from 

 the Bay of Biscay, S. decipiens from between 100 and 

 200 fathoms, and S. bipunctata only in open vertical 

 hauls made between 50 and 200 fathoms to the surface, 

 the total yield being only 7 specimens. Ritter-Zahony 

 ('10 b, p. 4) records both from the Irish Sea, but, in re- 

 gard to 8. decipiens, says: "S. decipiens is purely meso- 

 planktonic and in the Irish area was only found at depths 

 varying from 164 to 1,150 fathoms." Concerning S. 

 bipunctata he says that it is "confined to the epiplankton. 

 . . . The quantity of S. bipunctata in the upper epiplank- 

 ton is larger than in the lower." Finally, both species 

 have been taken in the Atlantic Ocean between 60° N. 

 and 8° S. but, while S. decipiens occurred only in open 

 nets from below 100 fathoms and in closing nets from 

 between 100 and 600 fathoms, S. bipunctata occurred 

 only in the epiplankton. From this evidence it seems 

 that wherever the two species occur in the same region 

 they are isolated by their manner of vertical distribution. 



S. LYRA AND S. GAZELLE 



S. lyra is a cold water, nearly eurythermal species 

 ranging from 73° N. to 7° 33' S., the highest temperature 

 recorded in connection with its capture being 18°. 6 C. 

 and the lowest l°.l C. It has been found in the epiplank- 

 ton of the arctic, sub-arctic and north temperate Atlantic, 

 and sub-antarctic Pacific Oceans, as well as in the meso- 



