MARINE DIATOMS OF THE PHILIPPINE ISLANDS 71 



G. marginatum Ehrenberg. It occurs also in the marine fossil deposit 

 at Lompoc, Calif., and abundantly in a living state in Bering Sea. 



COSCINODISCUS VARIOLATUS Castracane 



(Castracane, Chall. Exp., p. 155, pi. 2, fig. 5.) 



I hardly feel ready to accept Rattray's contention that this is only 

 a variety of C. denarius A. Schmidt. (See Rattray, Rev. Cose, 

 p. 57, and compare with Schmidt, Atlas, pi. 57, figs. 19-21.) But if 

 this is so, it is another case where the same diatom is common to 

 Campeche Bay and the Philippine Islands. Castracane's type came 

 from the Philippine Islands and G. denarius is reported by Schmidt 

 from Campeche Bay. 



Genus CRASPEDODISCUS Ehrenberg 



CRASPEDODISCUS INSIGNIS A. Schmidt 



(Schmidt, Atlas, pi. 66, fig. 2.) 



A study of this diatom suggests the question if this is not better 

 regarded as a species of Endictya. 



Genus CYCLOTELLA Kutzing 



CYCLOTELLA CRASSILINEATA, new species 



Plate 14, fig. 6 



Valve circular, somewhat transversely undulate; an outer area, 

 forming a band one-third the radius in width, strongly marked with 

 closely set radiating moniliform costae, their beading being rather 

 widely separated; within this band a circular central area, sparsely 

 punctate with irregular dots. 



Diameter 0.039 to 0.051 mm. 



Type.— Cat. No. 43615, U.S.N.M. 



CYCLOTELLA STRIATA (Kutzing) Grunow 



(Van Heurck, Synopsis, pi. 92, figs. 6-10, 12-15; Schmidt, Atlas, pi. 223, figs. 

 9-20.) 



Genus CYMATONEIS Cleve 



CYMATONEIS CIRCUMVALLATA Cleve 



(Schmidt, Atlas, pi. 212, fig. 48.) 



It seems to me Cleve's removal of this diatom and C. sulcata from 

 Navicula into his new genus, Cymatoneis, is an aid to classification, 

 although he subsequently abandoned the idea. It is one of the few 

 proposed new genera into which he tried to break up the unwieldy 

 genus Navicula that seems to be sufficiently unlike the typical Navi- 

 cula structure to be safely usable. It certainly is no more like the 

 Navicula image, as it has gradually shaped itself in the minds of dia- 

 tomists, than Scoliopleura or Brebissonia or Tropidoneis. Its sharply 

 defined central area, its sigmoid shape, its unique rhaphe terminating 

 at each end in a spine, and its sui generis style of beading give to it 

 35035—25 6 



