334 BULLETIN OF THE BUREAU OF FISHERIES 



the same relative position on the slope. Farther offshore, where the warm surface 

 stratum is thicker, Eukrohnia probably tends to keep still deeper. 



From this main area of distribution it works into the Gulf of St. Lawrence via 

 the Laurentian Channel, and into the Gulf of Maine via the eastern channel. It 

 likewise reaches the deep sinks between the Nova Scotian fishing banks, as Huntsman 

 (1919) showed, recent examples of which are its occurrence at two stations off Shel- 

 burne (20074 and 20075) in March, 1920. Generally speaking, the farther in from 

 the continental slope, the less plentiful is Eukrohnia. 



Other cluetognatlis 



The species just mentioned completes the list of glass worms so far recorded from 

 the inner parts of the Gulf of Maine, nor are any others to be expected there unless 

 as rare and accidental stragglers; but it would be no surprise to find any of the 

 chastognaths known from any part of the North Atlantic at one level or another 

 in the oceanic basin abreast of the gulf. In fact, Sagitta enflata, a tropical species 

 common in waters of southern origin off the east coast of North America " appeared, 

 with other tropical organisms, in the tows over the continental slope in 1914 [stations 

 10218 and 10220]; off Marthas Vineyard in 1915 [station 10333, one specimen]" 

 (Bigelow, 1917, p. 298). Pterosagitta draco, similarly tropical in origin, was repre- 

 sented by about 50 specimens in the 60-meter haul off the slope of Georges Bank on 

 July 21, 1914 (station 10218). Previous to that time we had taken it over the slope 

 abreast of Delaware Bay and Chesapeake Bay in July, 1913 (Bigelow, 1915, p. 299), 

 and Huntsman (1919) has since recorded it at the outer stations of the Canadian 

 fisheries expedition off Cape Sable and off the mouth of the Laurentian Channel in 

 July and August, 1915. Along the American littoral and off the Grand Banks region 

 these two species are among the most reliable of tropical indicators. Watch should 

 therefore be kept for them in the Gulf of Maine, where it is not likely that they 

 could long survive the low temperature. 



TOMOPTERIDS 



Tomopteris catharina (Gosse) " 



The curious pelagic worm, Tomopteris, not uncommonly appears in the plankton 

 of the Gulf of Maine, though never forming an important constituent of it, quantita- 

 tively speaking. So far the well-known T. catharina is the only species of the genus 

 which has been detected regularly within the southern rim of the gulf. 



In the western Atlantic this species is Arctic-boreal, having been recorded in 

 abundance on the Newfoundland Banks (Apstein, 1900) and in the Laurentian 

 Channel (Huntsman, 1921); southward, also, over the continental shelf about to 

 latitude 39° 30' (station 10069, July 19, 1913; Bigelow, 1915, p. 301); but it does 

 not occur in the Gulf of St. Lawrence, except as carried thither in the inflowing 

 current around the northern side of Cabot Strait or via the Strait of Belle Isle. 



" This Tomopteris has usually been called T. helgolandka (e. g., by Apstein, 1900; by Reibisch, 1905; and by Southern, 1911) ■ 

 but Rosa (1908) and Southern (1911) have shown that the common Tomopteris of the North Sea region was first described under 

 the specific name catharina, which consequently was adopted by Huntsman (1921). For accounts of Tomopteris and diagnoses o 

 its several species see Apstein (1900), Reibisch (1905), and Huntsman (1921) 



