KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 407 



in central mass. Multiple fission 2>i'oduces zoospores with girdle, one flagelknn, 

 and tentacle. Diameter, 200-120tV. Cosmopolitan in neritic, marine plankton. 

 One sj)ecies, Noctiluca scintillans, the type of the genus. 



Comparisons 



This genus differs markedly from PavUlardia in the excessive vacuolation 

 of its cytoplasm, in the degeneration of the girdle, reduction of the transverse 

 flagellmn, and dee^) excavation of the sulcus in the region of the cytostoine. 

 These contrasts result from the inflation due to the hydrostatic vacuoles. 



It resembles PavUlardia in the posteriorly located tentacle and in the be- 

 havior of this organ, as well as in the extension of the sulcus from near the apex 

 to near the antapex. 



Synonymy 



This is discussed in connection with that of the onl,y species, Noctiluca 

 seintillans Macartney. The flagellate described from fresh water by Fabre- 

 Domergue (1889), as ProuocfiJuca pclagica, does not appear to be a dinoflag- 

 ellate or to have any immediate relation to this genus. 



There is but one valid species in the genus, N. scintillans, which is here 

 designated as the type. All others described in the genus appear to be 

 s^Tionyms. 



Noctiluca scintillans (Macartney) 



Text figui'es KK, 1-6 



"Medusa marina" Slabber (1771, fide Ehreiiberg, 1834, for date), p. 67, pi. 8, figures 4, 5. 



Medusa scintillans Macartney (1810), pp. 264-265, pi. 15, figs. 9-12. 



Slabhcria Oken (1815). 



Noctiluca miliaris Suriray Mss, Lamarck (1816), pp. 470-472. 



Mammaria scintillans, Ehrenberg (1834), p. 559. 



"Noctiluca marina," Ehrenberg (1834), p. 559. 



Nocliluca miliaris Suriray (1836), pp. 1-16, pis. 1, 2. 



N. banksii? var., Ehrenberg (1834), pp. 509, 510. Lapsus for Noctiluca, a crustacean. 



N. punctata Busch (1851), p. 199, tig. 1. 



N. omogenea Giglioli (1870), p. 490. 



N. pacifica Giglioli (1870), p. 491. 



Diagnosis. — Body inflated, vacuolated, broadly reniform to sulispheroidal ; 

 girdle reduced to proximal remnant; sulcus forming reentrant cytostome, ex- 

 tended anteriorly to apex in a straight trottgh ; longitudinal flagellum short, 

 transverse one reduced to a mobile tooth; prcliensile tentacle at posterior end 

 of sulcus ; nucleus with Ijeaded chromatin, cytoplasm containing nucleus massed 

 neai- sulcus; scattered phosphorescent oil globules, pellicle jfirm ; no diromato- 

 phores; nutrition holozoic. Small zoospores with longitudinal flagellum. girdle 

 and tentacle, formed l)y multi])le fission. Diameter of adult, 2()0-12(XK rarely 

 2000/^. Cosmopolitan in neritic, marine plankton. 



