i8 



THE SCIENTIFIC AND ECONOMIC ASPECTS 



The following list, intended for cc 

 above tat)le, shows the plankton species 

 in tow-ncuings, together with the synib( 



ZOOPLANKTON. 



Acartia Clausi, Giesbr + 



Anomalocera Pattersoni, R. Temp. r 



Calanus finmarchicus, Gunn -f 



Centropages typicus, Kroyer c 



Metridia lucens, Boeck rr 



Microsetella atlantica, Brady rr 



Oithona similis, Claus r 



,, plumifera, Baird rr 



Pseudocalanus elongatus, Boeck ... + 



Temora longicornis, O. F. Mull ... cc 



Caradid larvae rr 



Evadne Nordmanni, Loven + 



Podon Intermedius Lilljeb r 



Zoeas rr 



Euphysa aurata, Forbes r 



mparison with series ABC and D of the 

 observed on several positions in Mounts Bay 

 1 of highest frequency in any one sample : — 



Muggiaea atlantica, Cunn r 



Obelia nigra, E. T. Browne r 



Plutei r 



Oikopleura dioica, Fol rr 



Fritillaria borealis rr 



Sagitta bipunctata, Quoy & Gaim + 



PHYTO PLANKTON. 



Rhizosolenia Stoltefothii, Perag ... cc 



,, alata, Brightw. ... + 



,, semispina, Hens. ... r 



Ceratium fusus, Ehbg -f 



tripos, O. F. Mull ... + 



Peridineum depressum, Ehbg ... r 



,, pallidum, Ostf rr 



Prorocentrum micans, Ehbg r 



The following list, intended for comparison with series E. of the above table, 

 shows the plankton species observed at several positions in Mevagissey and St. Austell's 

 Bays in tow-nettings, together with the symbol of highest frequency in any one sample : 



ZOOPLANKTON. 



.Acartia Clausi, Giesbr -|- 



Anomalocera Pattersoni, R. Temp, rr 



Calanus finmarchicus, Gunn + 



Centropages typicus, Kroyer cc 



Corycaeus anglicus, Lubb rr 



Oithona similis, Claus rr 



Pseudocalanus elongatus, Boeck ... + 



Paracalanus parvus, Claus rr 



Temora longicornis, O. F. Mull ... cc 



Caradid larvae + 



Evadne Nordmanni, Loven c 



Podon Intermedius Lilljeb r 



Zoeas rr 



Muggiaea atlantica, Cunningham... rr 



Obelia nigra, E. T. Browne r 



Phialidium temporarium, E. T. 



Browne rr 



Plutei rr 



Oikopleura dioica, Fol r 



Fritillaria borealis rr 



Sagitta bipunctata, Quoy & Gaim -f 



PHYTOPLANKTON. 



Rhizosolenia Stoltefothii, Perag ... cc 



,, alata, Brightw. ... + 



,, semispina. Hens. ... r 



Ceratium fusus, Ehbg -f 



tripos (O. F. Mull) ... + 



Dinophysis acuta (Ehbg) rr 



Peridineum depressum. Bail r 



Prorocentrum micans, Ehbg rr 



the touch. The single species responsible for this condition 

 was found to be Rhizosolenia Stoltefothii Perag., in the pro- 

 fuse gatherings of which, amounting in one sample to 29 cc. 

 of material (a five min. surface haul with the fine net), were 

 also to be observed in comparative scarcity one other species 

 of diatom, Rhizosolenia alata Bright, and certain Peridiniales. 



The phytoplankton, however, did not appear to be evenly 

 distributed throughout the whole area, but occurred in greater 

 abundance in patches toward the centre and eastern outer 

 quarter of the Bay. At one position about half a mile 

 S.E. X S. of St. Michaels Mount, a slight but comparatively 

 clean sample of zooplankton was obtained, but about three 

 miles farther to S.E. of this station phytoplankton again 



