120 



PROF. W. A. HERDMAN ON THE DISTRIBUTION 



is 2571. Swarrns of this oceanic species (fig. 18) in summer may possibly be 

 connected with an inflow of Atlantic water ; but probably also large numbers 

 appearing locally in enclosed areas may be the result of reproduction and 

 development in situ. 



In some cases Aaartia has been found in unusual abundance quite close to 

 the shore, and even in water of low salinity. 



Towards the end of September, 1917, we emptied for cleaning purposes 

 the large open-air fish-ponds at the Port Erin Biological Station, and when 

 most of the water had been pumped out we noticed that what remained was 

 swarming with small Copepoda. Every bucket and jarful that one removed 

 for inspection was found to be densely crowded — as densely, in fact, as an 

 average jar of plankton representing the contents of a standard haul. Some 

 buckets of these Copepoda were used for feeding the lobster larvae and 

 some of the smaller fish and other animals in the Aquarium, and a small 

 sample that was preserved was found to be a practically pure gathering of 

 Acartia clau.ii. One specimen of Centropages was present in the tube amongst 

 many thousands of Acartia, when Mr. Scott took the photo-micrograph shown 

 in fig. 18. 



Temora. 



Temora longicornis (Mull.) is a very local species, which may be found on 

 occasions swarming in great abundance in small areas of the sea, generally 

 close to land. It is a summer species and its maximum is generally in June 



Fig. 19. — Temora longicornis from the stomach of a Mackerel. 

 From a photo-micrograph by A. Scott. 



or July, but was in May in 1912, when the large hauls of 50,400 and 83,400 

 were taken on the 17th and 20th respectively. Other large hauls of this 



