DINOFLAGELLAT^ — IIISTIO.VEIS 251 



June: area between 10" N. 52" ^^^, Madeira, 40" N. :-57" W. and 



Porto Rico. 

 July: area between the Azores, 41° N. 58' \V., H;]- N. 74' 



W. and 15 N. 71° \V. 

 August. ■ 14° N. 70° W. to 84- N. 73- M^; 40' N. 59" W. to 



45' N. 43° W.; Azores. 

 September: S. of Cape Yerde Islands; sparingly from ()- N. 



53° W to the Azores; 20"— 38' N. 74° W 

 Ocroher: 21' S. 3fi' W.;Caribbean Sea; 34' N. 74" W.; Azores. 

 Xovember: 2()'— 24' S. 30°— 29" W.; 13" S. 27" W. to 0' S. 



32' ^y.■, 18' N. 57° W ; 22' N. 53' W.; 29" N. 43' W ; 



Azores to 34° N. 10' W. 

 Ih'ccinber: 26' S. 45' W.; 18' N. 67' W. to 25' N. 52' "W.; 



34' N. 38° W.; area between the Azores, Gibraltar and the 



Canaries. 

 1899 January: area between the Canaries, Madeira and Gibraltar. 

 March: 21°— 24' N. 43'-40' W'.; 35'" N. 16' W. 

 April: 32'— 36° N. 75°— 74° W. 

 May: 29'— 25" S. 9'— 7' E.; 36' N. 75' W. 

 June: 17' S. 2° W. to 9 N. 25' W.; 24' N. 14° AV.; 27' N. 



39' W. 

 July: 11°— 12' N. 26'— 27' W,; 32- N. 41° W to 40' N. 



3S' W. 



Temperature: 22.s, mean of 150 obs., max. 28, min. 17. 



Salinity: 36. 12, mean of 120 obs., max. 37.63, min. 33. 20. 



Plankton-type. This species is one of the most characte- 

 ristic organisms of the Desmo-plankton. It occurs outside the Atlantic 

 in the Adriatic, Mediterranean, Red Sea, Indian and Pacific. In the 

 Atlantic the area of distribution is the tropical and subtropical region, 

 between Africa and America, at least from. 29° S. to the Azores, 

 where it occurs the whole year. The northern limit in the west is 

 during the the winter about 35° N. The. northern limit advanced in 

 May beyond 40' N. nearly to 45°, but in September it had retired 

 below 40', but on the other hand the area of distribution moved in 

 November — January towards the Canaries and Gibraltar. —7 T). 



