EASTERN C'A.YADZAA' PLANKTON 



87 



DISTRIBUTION— Confinuerf. 



C.G.S. Princess. 



Station No 20 21 42 45 45 



Depth of Haul (m. );....-■ 10(^0 (V) 10(K0 (V) 100-0 (V) 30-0 (V) Ca. 40-0 (T) 



Length (mm.) 25 30 35 ca. 25 30-40. 



Number 1 1113 



C.G.S. Thirty-three. Motor-boat Prince. 



!Srof&aui(m.);.v.v.v.v.-.v.-.v.:.-v.-.v.:;::::;:: s^'m nlom 



Length (mm.) 20-35 30 



Number 10 1 



Vertical. — This species was found at the surface and down to a considerable depth. 

 The data indicate a daily migration to and from the surface. With one exception 

 ("Acadia" Station 86) it was obtained in the near-surface tows only between 6 p.m. 

 and 6 a.m. It occurred in the vertical hauls and was absent. from the near-surface 

 tows at eleven stations, taken between 6 a.m. and 6 p.m. For the Irish coast Southern 

 (1911, p. 12) records it from the surface to below 1,000 fathoms, but fails to find any 

 correlation between its vertical distribution and the hour of the day. 



Horizontal. — On the ]\ray-June cruises, the largest numbers were obtained at 

 "Acadia" Stations 19 and 21 on the Green bank oif the south coast of Newfoundland. 

 On the July-August cruises, the Only station at which the species was found in any 

 abundance was "Acadia" Station 83, which was off St. Pierre island, near Newfound- 

 land. The centre of abundance of the species is, therefore, the Newfoundland banks. 

 This is in agreement with the finding of the species in greatest abundance on the 

 Grand Banks of Newfoundland by the Plankton-Expedition, as recorded by Apstein 

 (1900, p. 45). 



From its centre of abundance on the banks off Newfoundland T. catharina is 

 distributed toward the northwest and toward the southwest and decreases in abun- 

 dance in each direction. On the May-June cruises it extended to the northwest along 

 the southern coast of Newfoundland into the gulf through Cabot strait, keeping to the 

 north side of the strait. Only a single specimen was obtained at each of "Princess" 

 Stations 20 and 21 just inside the strait and not one was obtained at any of the 

 remaining stations in the gulf. This seems to have been the extent of its distribution 

 inside the gulf at that time. It indicates that very little of the coastal water is passing 

 westward along the southern coast of Newfoundland into the gulf. If the current 

 flowing into the gulf through Cabot strait off cape Ray had any strong component 

 from the water covering the banks off the south east part of Newfoundland, this species 

 would undoubtedly be well distributed inside the gulf. 



It is abundant at the mouth of the Laurentian channel and extends from that 

 region t'»ward the southwest in a broad band along the edge of the continental shelf, 

 as found at "Acadia" Stations 10-13. At first sight it would appear that T. 

 catharina is being carried Vy a current from the Newfoundland banks acro=s the mouth 

 of the Laurentian channel to the southwest. It may be otherwise. Its presence in 

 moderate abundance at " Ac dia" Station 34, places it in the outer part of the outflow- 

 ing Cape Breton current, which it enters from the north. In the outer part of this 

 current it would be carried to the mouth of the Laurentian channel and then to the 

 southwest along the side of the continent. 



In the area of distribution outlined above (See fig. 1), the species was lacking at 

 onlv two stations. At both of thes^- station'j, "Acadia'-' Stations 20 and 22, only 

 surface hauls were made, and at the latter station the haul was made during the day, 

 when it woi^ld' not be expected at the surface. 



On the July- August cruises certain differences in the distribution are to be 

 noticed. Except on the Newfoundland banks, only solitary specimens were obtained in 

 the vertical hauls and these were at widely separated points. It is again present jus+ 

 inside Cabot strait on the north at "Princess" Station 45 off cape Anguille and at 



