CHAPTER XV 



GYMNODINIIDAE : TORODINIUM 



TORODINIUM -eii. nov. 



Text figure II 



Gymnodimum, Pouchet (1885a), in part, p. 67, pi. 4, fig. 29. 

 Gymnodinimn, Lemmermann (1899), in part, p. 358. 

 Gymnodinium, Schiitt (1895), in part, pi. 165, pi. 23, fig. 74i_,„. 

 Gymnodinmm, Paulsen (1908), in part, pp. 97, 98, fig. 132. 



Diagnosis 

 Body elongate, epicone several times the length of the h^'i^ocone in length, 

 girdle and hypocone forming an augnr-shaped cone at the antapex; girdle 

 forms a descending left spiral of slight displacement; sulcus with very long 

 ajiical loop with torsion of ahout 0.5 turn posteriorly and straight antero- 

 longitudinally, running most of the length of the body nearly to the apex; 

 nucleus faint, greatly elongated; rhabdosomes linear, sinistral, longitudinal; 

 marine, eupelagic. Two species; the type, Torodinium teredo (Pouchet), M^as 

 described by Pouchet (1885a, p. 67, pi. 4, fig. 29) as Gymnodinium teredo. 



Desceiption 

 The marked torsion of the sulcus, amounting to 0.5 turn, equivalent to 

 that in the simplest species of Cochlodinium and without parallel elsewhere 

 in Gymnodinimn, serves to exclude Gym- 

 nodinium teredo from the genus in which 

 Pouchet (1885«) described it, and in 

 which all subsequent investigators have 

 left it. In all species of Coehlodininni, 

 as well as of Gymnodinimn (except in G. 

 fjJaHcum Lebour), the anterior flagellar 

 pore is at least premedian and never 

 ])ushed back almost to the antapex, as in 

 T. teredo (fig. II). In correlation with 

 this ])osterior dislocation of this pore and 

 the accompanying girdle in Torodininm, 

 the stilciis stretches anteriorly almost to 

 the a])ex, retaining 0.5 turn or more of the 

 charactei'istic torsion of the apical loop, 

 but exhibiting little or no torsion in its 

 very much foreshortened intercingular 

 and antai)ical portions. This unique ar- 

 rangement of these fundamental organs. 



Fig. II. Torodinium gon. nov. 1. Torodinium 

 robustum sp. nov. Left lateral view. 2. Ventral 

 view of antapioal region. .3. Right lateral view 

 of antapioal region of same figure. 4. Torodinium 

 teredo (Pouchet). After Schiitt (1S96, pi. 23, fig. 

 74j). Abbreviations: epi., epioone; (jir., girdle; 

 hyp., hypocone; long, ft, longituilinal flagellum; 

 n., nucleus; pus., pusule; rod., roillets or rhabdo- 

 somes; sulc, sulcus; tr. fl., transverse flagellum. 

 X 500. 



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