102 ] The Classification of Lower Organisms 



Family 7. Noctilucida [Noctilucidae] Kent Man. Inf. 1: 396 (1880). The single 

 species Noctiluca scintillans (Mackartney) Kofoid and Swezy (1921; usually known 

 as A^. miliaris Suriray ) is a predatory marine organism, the subglobular cells reaching 

 dimensions exceeding 1 mm., luminescent when stimulated and accordingly contrib- 

 uting to phosphorescence at sea. Each cell is marked by an extensive depression 

 representing the sulcus; the girdle is obsolete. A part of the area of the sulcus func- 

 tions as a cytostome. A tooth in the sulcus represents the transverse flagellum. Present 

 are a longitudinal flagellum, minute in proportion to the cell, and a prominent 

 tentacle. 



Mitosis in Noctiluca has been studied by Calkins (1899), van Goor (1918), and 

 Pratje (1921). Adjacent to the nucleus there is a body of differentiated cytoplasm, 

 as large as the nucleus, called by Calkins the attraction sphere. Before mitosis, the 

 tentacle and flagellum are absorbed. The attraction sphere becomes elongate and 

 its central part becomes converted into fibers. The nucleus becomes appressed to, 

 and curved about, the bundle of fibers, and the numerous elongate chromosomes 

 assemble against this. The two curved margins of the nucleus draw apart along the 

 bundle of fibers, appearing to draw the daughter chromosomes with them. Division is 

 completed by constriction of the nucleus and disappearance of the fibers, leaving a 

 daughter attraction sphere in association with each daughter nucleus. This peculiar 

 mitotic process is probably of no phylogenetic significance, being, like the organism 

 in which it occurs, an aberrant by-product of evolution. 



Nuclear division may be followed by division of the cell into two, the entire 

 process requiring from twelve to twenty-four hours. Alternatively, the nucleus may 

 divide repeatedly, each division requiring from three to four hours; the numerous 

 nuclei produced are budded off from the cell in small uniflagellate spores. Ischikawa 

 ( 1891 ) saw conjugation of pairs of cells, and van Goor stated that this is a preliminary 

 to the production of spores; Pratje, on the other hand, could find no evidence of 

 conjugation. The spores are believed to give rise by direct growth to cells like the 

 original one. 



Family 8. Leptodiscida [Leptodiscidae] Kofoid 1905. Large dome-shaped preda- 

 tory marine organisms with small flagella or none. Leptodiscus R. Hertwig (1877) 

 was placed by Biitschli in order Cystoflagellata as the sole genus in addition to 

 Noctiluca; Craspedotella is a comparatively recent discovery of Kofoid. 



Family 9. Blastodinida [Blastodinidae] Chatton in Arch. Zool. Exp. Gen. 59: 

 442 (1920). Ordre Blastodinides Chatton in Compt. Rend. 143: 981 (1906). Fam- 

 ilies Apodinidae, Haplozoonidae, Oodinidae, and Syndinidae Chatton op. cit (1920). 

 Dinoflagellates which are parasitic chiefly in copepods and tunicates, also in other 

 animals and in diatoms. As a general rule, after the parasite has grown to a certain 

 size, and a multiplication of nuclei has taken place, a part of the protoplast undergoes 

 division to form gymnodinioid zoospores, while the remainder resumes growth in 

 the host. Schizodinium, Blastodinium, Apodinium, Chytriodinium, etc. 



Order 4. CiUoflagellata Claparede and Lachman Etudes Inf. 1: 394 (1858). 

 Family Peridinaea Ehrcnbcrg Infusionsthierchcn 249 (1838). 

 Family Dinifera Bergh in MoVph. Jahrb. 7: 273 (1882). 

 Order Dinoflagellata BiitschU in Bronn Kl. u. Ord. Thierreichs 1, Abt. 2: Inhalt 



(1887). 

 Subclass Peridiniales Engler in Engler and Prantl Nat. Pflanzenfam. I Teil, Abt. 



lb: V (1896). 



