SEA-FlSHEUlKS LABOHAfORY. 



215 



progressive increase iu the numbers of Oitlwna similis 



during the three years is noteworthy. 



The greatest single hauls of Copepoda (taken with the 



ordinary " coarse " net) in Port Erin Bay, during 1911, 



were as follows : — 



Species. 

 Oithona similis , 



Pseudocalanus elongatus 



Paracalanus parv^is 



Acartia clausi 



Temora longicornis 



Calanus helgolaiidicus .. 



Some of these are very large hauls indeed for 

 Copepoda. 



If we arrange all the species of Copepoda (15) 

 recorded on our forms in liJll in two series, according 

 as they are supposed to be " Oceanic " or " Neritic," we 

 get the following result : — 



Oceanic. 



Calanus helgolancUcus. 

 Pse udocalanus elongat us. 

 Oithona similis. 

 Paracalanus parvus. 

 [Acartia clausi] 

 A nomalocera patersoni. 

 Microcalanus pusillus. 

 Metridia lucens. 

 Candacia arrnata. 



Neritic. 



Temora longicornis. 

 [Centropages hamatus] 

 Euterpina acutijrons. 

 Isias clavipes. 

 Parapontella hrevicorn is. 

 Labidocera wollastoni. 



A few of these are undoubtedly oceanic and neritic 

 respectively, for example Calanus lielgolandicus is 

 typically oceanic, while Isias clavipes is a shore form; 

 but other cases are more doubtful. One would expect an 

 oceanic form which only invades a shore area on 

 occasions to have a more or less periodic distribution, but 



p 



