95 



REPORT ON THE 



PLANKTON COPEPODA OF THE CHANNEL ISLANDS. 



BY ISAAC 0. THOMPSON, F.L.S. 



A collection of thirty-nine bottles containing plankton, taken by 

 tow-net at various dates between 1887 and 1897 about Jersey and 

 Guernsey was lately placed in my hands for examination, by Mr. Hornell. 

 the Director of the Jersey Biological Station. With the exception of 

 one bottle marked December 7th (1892) all the material was taken 

 between the months of February and September, By far the largest 

 proportion of the material is Copepoda, with a profusion of Nauplii in 

 those bottles collected during early Spring. Amphipoda, Cumaceae. 

 Appendiculariae, Mysidee, Sagittal, &c, occur plentifully. It is with 

 the Copepoda alone, however, that this report has to do. Thirty-one 

 species are represented in the collection, as follows : — 



Family : — Calantd^e. 



1. Calanm jinm&rchicus, Gunn. 



This species, so commonly distributed throughout our seas. 

 was present in about 25 per cent, of the bottles, but in none very 

 abundantly, with the exception of that collected in December. As 

 the chief food of the Greenland whale it is found profusely distri- 

 buted in the Arctic seas. A parasite of the Galanus, Micrmiscus 

 calani, G. 0. Sars, was found attached to one of the specimens. 



2. Calanus propinpws, Brady. 



One specimen of this rarer species was taken in St. Aubin's 

 Bay, Jersey, in April. 



3. Pseudomlmwj elongatus, Baird, 



Probably the commonest of British Copepoda. It occurs in all 

 the gatherings plentifully. 



4. Acartm clansii, Giesbrecht. 



Almost as plentiful as the last species. 



5. Acartin discawiata, Giesbreeht. 



A few specimens were taken in July, ia St. Aubin's Bay, Jersey. 

 It is easily distinguished from the previous species {A, elausii) by 

 its short, rounded caudal stylets. 



6. Temora fongicornis, Mull. 



A very common British species, plentiful in nearly all the 

 bottles, but rarely found except in British seas. 



7. Isias clavijpes, Boeck. 



This easily recognizable species occurs sparingly in several of 



