296 bulletin: museum of comparative zoology. 



surface habitat makes it easy to establish the hydrographic conditions 

 in which it was living, the temperature range being 54°-76° ; the salin- 

 ity 32.1%o to 35.25%o. 



In European waters, likewise, Anomalocera pattersoni is chiefly 

 found on the surface (Scott, 1911) though it inhabits ratjier Salter water 

 there, and our catches support Scott's statement that it is a creature 

 of the open seas, to the extent that it was not found in enclosed bays 

 or harbors. But its regular occurrence in the Gulf of Maine shows 

 that it is not typically oceanic in the sense in which Pleuromamma or 

 Rhincalanus may be so described. 



The copepods discussed so far are more or less regular inhabitants 

 of the Gulf of Maine ; but several species were found outside the conti- 

 nental shelf which enter the Gulf only sporadically if at all. Such 

 are Rhincalanus nasutus, Euchirella rostrata, the several species of 

 Pleuromamma, Euchaeta major, E. minor, and Candacia armata. 

 The first of these was taken at all three off shore stations (Fig. 69), 

 and nowhere else, the total number of specimens detected being only 

 forty-nine. The salinity was about 35%o-35.25%o which agrees 

 very well with the high salinities of 34.9%o to over 35.6%o from which 

 it is recorded by Cleve (1900) and Farran (1910). The temperatures 

 can not be established exactly, the catches all being in open nets from 

 considerable depths: but the absence of the species on the surface 

 and in the hauls from twenty fathoms, and its occurrence in hauls 

 from 175 fathoms (Station 10064), 190 fathoms (Station 10071) and 

 120 fathoms (Station 10076) leads to the conclusion that it was living 

 at a temperature of about 48°-55°. According to Cleve (1900, p. 139) 

 the mean temperature for the species is 59°. But, as Farran (1911) 

 points out, its range of temperature is very great. Its occurrence in 

 the deeper layers at the edge of the Gulf Stream, and its absence from 

 our coastal waters, whence it has never been recorded, agree with its 

 oceanic habitat, for it is only in the sweep of the Atlantic current that 

 it is recorded by the International Committee. 



Pleuromamma robusta was taken in some numbers (about 400 speci- 

 mens) in the deep haul (175-0 fathoms) at Station 10064; two speci- 

 mens were detected in the haul from twenty fathoms at Station 10071, 

 and a single specimen in the Gulf of Maine (Station 10100, 90-0 

 fathoms). Thus it, like Rhincalanus, was living in water of high 

 salinity, from about 33.8%o in the deeps of the Gulf to upwards of 

 35.2% (Station 10071). And it, too, is rarely taken near the surface 

 anywhere (Scott, 1911), though widely distributed in the North Atlan- 

 tic. Pleuromamma xiphias and P. rotundum, likewise oceanic, were 



