CHAPTER XIV 



GYMNODINIIDAE : COCHLODINIUM 

 COCHLODINIUM Scliiitt 



Text fi^ires 0, FF-HH 



Gymnodinium, Scliiitt (1895), in part, pi. 22, fig. 72; pi. 23, figs. 75, 76; pi. 24, fig. 77; pi. 



26, fig. 93. 

 Cochlodinium Scliiitt (1896), pp. 5, 6, figs. 1, 7. 

 Cochlodinium, Paulsen (1908), in part, pp. 103-105, figs. 142-145 (fig. l-^-^^Gyrodinium 



longum). 



Diagnosis 



Gymnodiniidae with torsion of the body of at least 1.5 turns; girdle a 

 descending left spiral of 1.5 or more turns, widely displaced; sulcus with or 

 without apical and antapical loops and a torsion of 0.5 or more turns. Nucleus 

 Ttsually in center or posterior part of bod_y, rarely anterior; perinuclear mem- 

 brane generally absent ; monilif orm chromatin strands distinct. Pusules usually 

 present, opening anteriorly into the anterior flagellar pore, posteriorly into the 

 posterior pore, frequently united at their extremities into one canal opening into 

 both pores. No nematocysts ; plasma varying from colorless to highly colored ; 

 chromatophores rarely present ; holozoic nutrition prevalent ; melanin or other 

 pigment granules sometmies present. Surface may be smooth or, less fre- 

 quently, striate. Encystment in thin-walled membrane frequent. Rarely a 

 tendency to colonial formation. Length, 27-200/*. All marine, eupelagic and 

 from warm temperate seas. Thirty species known. 



Orgaitology 



In the elongation of the girdle and sulcus and the torsion of the body 

 resulting therefrom the genus GocModinium shows the greatest development in 

 the G^Timodinioidae, or indeed in the Dinoflagellata. The length of the girdle 

 (fig. FF, gir.) is intimately correlated with the torsion and constriction of the 

 body in Coclilodiniam, differing in this respect from the genus Pouchefia, where 

 the length, course, and torsion of the sulcus are the outstanding features of 

 its organization. The greater development of the apical and antapical loops 

 of the sulcus so striking in Pouchctia is foreshadowed in GocModinium in 

 C. clnrrissimnm (fig. GG, 2), C. winiafion (fig. GG, 6), and C. afromacidafum 

 (fig. HH, 6). 



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