SURFACE AND DEEP TOW-NETTING. 161 



G. centralis, occasional. 



Nitzschia paradoxa, frequent. 



Fragilaria hijalina, occasional. 



Synedra Gaillonii, occasional. 



Thalassiosira Frauenfeldii, occasional. 



Eunotia sp., occasional, a fresh-water form. 



Bhabdonema adriaticum. 



Grammatophora marina. 



Navicula gr eg aria. 



Isthmia enervis. 



Par alia sulcata. 



Cyclotella striata, var. ambigua. 



Ghcetoceros boreale. 



C. pelagicum. 



C. secundum. 



G. fucellatum. 

 The few Foraminifera found were at or near the surface, 

 as also were the few Medusae taken. 



Several Pleurobrachia were in the bottom net, but none 

 in the surface ; and an enormous number of Sagitta were 

 brought from the bottom, but none were found near the 

 surface. 



A few fish ova were taken by the bottom net only. The 

 distribution of the remaining plankton taken can be seen 

 from the table (p. 158). 



From these comparative results of the gatherings taken 

 from upper and lower strata, it is clear that both should 

 be noted at any given time, as there is much to be yet 

 learned as to the effects of temperature and other influences 

 upon the minute forms of life of our seas. It is hoped 

 that we may be able, say at the four seasons, during the 

 rest of the year, to continue observations on a similar plan. 

 To obviate the difficulty of arranging a bottom tow-net, 

 there is the alternative method of pumping water directly 



