KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 411 



in the peri)5liery, are numerous small oil globules, the centers of the luminescent activity of the 

 animal. 



There are no chromMtojihores. The color is an ojjaleseent greenish blue, sometimes tinged 

 with yellowish green, or even ochraceous yellow in the central mass of cytoplasm. 



Nutrition is holozoic. NocUluca is omnivorous, capturing active organisms such as Pcn- 

 dindnm, Ganyaiilax, and nauplii. as well as passive diatoms, metazoan ova, and even engulfing 

 inorganic particles such as .small grains of sand. 



Multiplication by binary fission is frequent. This results in typical dinoflagellate chain 

 arrangement of the two daughter organisms (fig. KK, 4), although the movements of 'the 

 tentacles and approaching plasmotomy soon obscure this relation. Early binary fission was 

 mifsinterpreted by Ishikawa (1891) as conjugation. Doflein (1916) states he has seen complete 

 fusion of cytoplasm and nuclei of two individuals. Mitosis (see Ishikawa, 1899; Calkins, 1899; 

 Doflein, 1900; and Jollos, 1910) is of the dinoflagellate type, with large sphere and beaded 

 chromosomes, but the beaded condition is most evident at mitosis. 



Multiple fission residts in the formation of numerous zoospores (fig. KK, 3) with girdle, 

 longitudinal flagt41um, incipient tentacle, and the general appearance of a small dinoflagellate, 

 but with no transverse flagellum. 



Di:kiF.xsioxs. — Diameter, 400-1200/*, rarely 200-2000/*; zoospores, length, 

 25-30/1; transdiameter, 10-15/*. 



OccTTRRENCE. — Abundant in San Diego Bay, San Pedro harbor, San Fran- 

 cisco Bay, and Puget Sound, and less so in the plankton off the Pacific Coast 

 of the United States, throughout the year, but more abundant in summer and 

 auttmin. It is apparently cosmopolitan in the neritic plankton of temperate 

 and tropical seas, but not typically pelagic in the high seas. It is not men- 

 tioned in Hensen's (1911) summary of the findings of the Plankton Expedition. 

 Karsteu (1905c/, h, 1907) lists it in the Yaldivia collections only from coastal 

 regions. Parker and Haswell's (1897) statement that NoctUnca is the cause 

 of the diffused phosphorescence of the sea should be modified by the restriction 

 to one of the causes of phosphorescence in neritic waters. "Pyrocijstis''^ re- 

 places it in the plankton of the high seas. 



Syxoxymy. — The nomenclature of NoctiJnca is fraught with difficulties 

 arising from fragmentary and incomplete descriptions by the earlier observers, 

 confusion, on their part, of NoctiJuca with other phosphorescent organisms, as 

 well as by its description under A-arious names. The name NocUluca miliaris 

 has, except for the deliberate reallocation of the organism by Ehrenberg (1834), 

 held almost undistvirbed sway in practically all the voluminous, original liter- 

 ature and in widespread citation in standard texts since 181(i, when Lamarck 

 used Suriray's manuscrij)t name in his Aniniaux sans vertehres. The law of 

 prioi'ity clearly calls for the specific name scintiUans Macartney (1810\ but 

 the determination of the generic name is fraught with difficulties. Any name 

 othei' than NoffiJnca rests on the most unstable premises, and even it is of 

 (juestiouable '\'alidit3\ 



The most extended discussion of the status of Noctiluca is found in 11 le 

 exhaustive review by Ehrenberg (1834) in his Das Leuchten des Meeres, though 

 it is not made witli a view to priority under any code of nomenclature. From 



