KOFOID AND SWEZY: UNARMORED DINOPLAGELLATA 103 



Poiicliet's industry and his exceptional opportunities at Conearnean for 

 studying the living dinoflagellates of the marine plankton greath^ enlarged our 

 knowledge of this group, especially of the unarmored forms. He added no less 

 than fifteen species to the list. Unfortunately for the systematists who followed 

 him, Pouchet 's pioneer work was so fragmentary and his conception of specific 

 limits so vague and changeable that his contriliutions are incorporated with 

 difficulty in our pi-esent system. He added to our knowledge of Pohjkrikos and 

 Noctiluca, but became involved in the latter 's puzzling relations to "pseudonoc- 

 tiluca" forms, without arriving at any clear conception of the relationships of 

 Noctiluca to the dinoflagellates. His greatest contribution was his discover}' of 

 the ocellate forms which he included in Gymnodiynum, but which now, as 

 PoHchctia, bear his name. He also contributed to our knowledge of the arctic 

 dinoflagellates in his account (1894) of the voyage of the "Manche" and of the 

 relation of dinoflagellates to the food of the sardine. 



Coincidentally with Pouchet's earliest work (1883) appeared Gourret's 

 monograph (1883) on the Marseilles dinoflagellates. This also was a pioneer 

 enterprise, and beyond recording a few new species and adding greatly to 

 s^Tionymical perplexities he contributed little to our permanent knowledge of 

 the group. His conception of the phylogenetic position of Gymnodinium as a 

 terminal derivative of the thecate GUnodininm and Diplopsalis is the reverse 

 of ^^•hat appears sound, and is on a par Avith his derivation of Amphidinium 

 from Dinophysis. 



The greatest single contribution made to this subject was that of Schiitt, 

 whose monograph on the dinoflagellates appeared in 1895 as part of the results 

 of the "Plankton" Expedition. Both in the number and variety of forms which 

 he figured and the careful and painstaking analysis of the structures and proto- 

 plasmic organization of these flagellates his work stands unrivaled. Seven of 

 the large folio plates are devoted to the members of the Gjaunodinioidae, adding 

 many new forms to those previously described. He unfortunately omits all 

 mention of the localities from which his material was obtained, hence his work 

 has little to offer in the distributional and geographical study of the dinofla- 

 gellates. 



In the following year (1896) the same author revised the system of classi- 

 fication of the dinoflagellates in Engler and Prantl's Pfianzcnfamilien. He 

 separated the thecate and non-thecate forms, and in the latter group distin- 

 guished the genera Spirocliniiim and Cochlodinium., with Pouchetia, a genus 

 which he had established the preceding year. The entire group he divided into 

 three divisions, the Gymnodiniaceae for the non-thecate forms, the Prorocen- 

 traceae and the Peridiniaceae for the thecate. With the Gynniodiniaceae he 

 placed the genus Pyrocystis, which had been described l\v ]\lurray in 1876. In 

 thus recognizing the systematic value of the distinction between the thecate and 

 non-thecate dinoflagellates he laid the basis of the present system of classifi- 

 cation. Klebs (1912) returned to the older system in placing the genus Amphi- 

 dininm in the Prorocentraceae. He also removed the thecate Glenodinium 



