280 DISCOVERY REPORTS 



species under the name of Cerataulina Bergonii said: " It was first described by me as 

 Zygoceras? pelagicum (Kanonbaaden " Haucks" Togter, p. 54) but from dried and mis- 

 shapen specimens. Consequently my description and figure leave much to desire and 

 I prefer the name given by Peragallo who accurately figured it." As Cleve was perfectly 

 satisfied that his Zygoceras? pelagicum was identical with Peragallo's specimen, Cleve's 

 epithet must be accepted as being the earlier one. If Cleve had included a description 

 of the genus Cerataulina in 1894, the authority would have to be credited to him. 

 Observed at Sts. 434, 481. 



Genus Bellerochea Van Heurck 

 Van Heurck, 1885 



Bellerochea indica Karsten. 



Karsten, 1907, p. 393, pi. 46, fig. 2. 



Cells shaped like dumbbells in girdle view, linear-lanceolate in valve view. United to 

 form flat ribbon-like chains. The poles of the valves are raised and slightly produced to 

 form large flattened processes which adhere closely to the corresponding processes of 

 the adjacent cell at both poles. Surface of valve somewhat undulating, slightly inflated 

 in the middle. When seen in girdle view in chain formation, the intracellular spaces are 

 large, and elliptic-lanceolate. Chromatophores : numerous short vermiform bodies. 

 Cell nucleus very prominent, occupying a central position. Polar axis 160/^ ; pervalvar 

 axis 16-20/^ ; intracellular space z\\x. at pervalvar axis. 



A large weakly siliceous pelagic form, common in the Indian Ocean. Observed at two 

 stations to the south-east of Cape of Good Hope, in ribbon-like chains of ten to thirty 

 cells in each chain. Although often associated with a coastal flora, it is probably holo- 

 planktonic. 



Observed at Sts. 425, 428. 



Genus Trigonium Cleve 

 Cleve, 1868 



The genus Trigonium Cleve was established upon Triceratium arcticum Brightwell. 

 Cleve was dissatisfied with the composition of the genus Triceratium Ehrenberg, and 

 perceived in Brightwell's species certain fundamental differences which he intended to 

 use as the basis of a new genus. The generic description of Trigonium was as follows : 

 " Huvudytan triangidar, sidoytan rektangelformig utan framspringande utskott eller homy 



Unfortunately this description did not prove sufficiently precise to exclude a large 

 number of forms which I do not think Cleve had any idea of admitting when the genus 

 was created. Mann in 1907 adopted Trigonium, which until then had been monotypic, 

 and added to it a large number of species which had been previously described under 

 the generic heading of Triceratium. These species did not bear the slightest resemblance 

 to the type species and entirely ruined the value of Cleve's work, which consequently fell 

 into disuse. The majority of them were triangular forms of Biddidphia possessing granu- 



