1911] Kofoid: The Genus Goinjaulax. 199 



GoHjjaulax pacifica described by me in the same year (April 13, 

 1907), but prior to the publication of Karsten's paper (Decem- 

 ber, 1907). It may therefore be dismissed as a synonym of 

 G. pacifica. 



A homonym (in botanical nomenclature) of Sfeiniella 

 Schiitt was established by Bernard (1908) for a single species, 

 S. Graevoiitzii {Protococaceae) for the reception of which I 

 here propose the generic name Steiiiedcsmus nom. nov. 



The relations of Amphidoma and Murrayella to Gonijaulax 

 are intimate, but our present knowledge of their skeletal inor- 

 phology is insufficient for final conclusions as to their standing. 

 In so far as our data go they are both genericall.y distinct. The 

 apical and antapical regions in both are difficult of analysis on 

 account of the small size of the plates and their firm adhesion 

 one to another. Amphidoma is distinguished from GonyaiUax 

 by six apicals and no precingulars, by the form of the apices, 

 by the feebly developed longitudinal furrow, equatorial, and 

 non-displaced, horizontal girdle ; Murrayella by its five post- 

 cingulars, the absence of a truncate apex, and by the form of the 

 longitudinal furrow. 



The genus Ceratocorys is distinguished by its five precingu- 

 lars, three apicals and one anterior intercalarj^ and by the 

 anteriorly located girdle. 



The genus Spiraulax Kofoid founded on Gonyaulax jolliffei 

 Murray and Whitting differs from Gonyaulax in the shortened 

 apical 1' (rhomb plate of various authors), the junction of pre- 

 cingular 1" and anterior intercalary i" across the miclventral 

 line, in the presence of a ventral notch in apical 1', and in the 

 absence of a ventral pore. See Kofoid (1911c). 



IV. Skeletal Fission 



Cell division in the genus Gonyaulax may take place in 

 thecate individuals and in this case it involves the division of 

 the enveloping theca. Fission of the cell mass which has rid 

 itself of its skeleton by ecdysis is possible especially in such 

 species as G. polyedra where this phenomenon is often seen, but 

 no conclusive evidence of cell division in the naked stage has 



