244 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



which is not motile, as is the flageUiim. Its length is about equal to the doi-soventral diameter or 

 less. It is possible that he is here confusing two distinct forms or that we have in this species an 

 extraordiaaiy mobility in the form of the body. 



DiMEXSioxs. — Leiigtli, 100-200^; transdiameter, 46-80^. 



OccuEREXCE. — This species was figured by Pouc-liet (1885o) from the 

 Atlantic off Concarneau, France, in June, and, at later dates (1892?;), from the 

 Atlantic off the Faroe Islands in August, and, in 1894, from the Ai'ctie Ocean 

 near Spitzbergen in August. 



Syxoxymy. — Lebour (191T?>') has figured a form which she calls G/jnuio- 

 dinium pseudonoctiluca Pouchet. The differences between the two forms are 

 too great, however, to place it with Pouchet 's species. The girdle forms a com- 

 plete circle at the anterior end, instead of turning jDosteriorly on the ventral 

 surface, where, in G. pscudonoctnuca, it reaches posteriorly beyond the middle 

 region of the body. Lebour 's species also possesses bright yellow chromato- 

 phores. It is therefore given species rank, with the name G. fulgens nom. sp. 

 nov. Pouchet 's record (1894) of this species from the Arctic Ocean at a tem- 

 perature of 2°-3° C may be looked upon with suspicion. It seems improbable 

 that the Gulf Stream could carrj', without change, organisms as frail and 

 delicate as these from the warm semitropical waters to the cold Ai-ctic Ocean. 



Comparisons. — In its cytoplasmic structure G. pseudonoctiluca recalls the 

 conditions found in G. pachydcrDiaium, G. dogieli, and G. amphora (figs. AA, 

 5, 1, 6). It differs greatly, however, from that group in its lack of a differ- 

 entiated ectoplasm. In the possession of this tentacle-like protrusion this 

 species might seem to be a connecting link between this group and the Xoeti- 

 lucidae. However, in so far as our knowledge goes, it appears that we are here 

 dealing with a protoplasmic extension of the edge of the sulcus of a temporary 

 nature, perhaps like that figured by Schiitt (1895) for G. rete, and by Zacharias 

 (1899) for G. zacliariasi. It is a tentacular pseudopodium, and not a flagellum 

 transformed into a tentacle, and is therefore not homologous with the tentacle 

 of Noctiluca. 



Gymnodinium punctatum Pouchet 

 Text figure BB, 18 



Gymnodinium punctatum Pouchet (1887), pp. 10.5-107, pi. 10, fig. 7. 

 G. punctatum, Lemmermann (1899), p. 359. 

 G. punctatum, Paulsen (1908), p. 108. 



Description. — This is a minute form with broadly ellipsoidal body in ventral view, compressed 

 dorsoventrally to 0.54 transdiameter, its length 1.33 transdiameters. The girdle is median in 

 position, dividing the body into subecjual parts. The epicone is hemispherical, the liypocone 

 slightly notched at the antapex. The nucleus is a large, chromat in-filled body in tlie epicone. A 

 minute red-pigment spot is present near the posterior part of the body. The sulcus and course 

 of the girdle were not figured by Pouchet (1887). Length, 10/n. Atlantic off Concarneau, France. 



