150 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



STICTODISCUS NITIDUS Grove and Sturt 



Plate 32, fig. 3 



(Schmidt, Atlas, pi. 131, fig. 7; compare Grove and Sturt, Oam. Diat., pi. 5 

 fig- 7.) 



The specimen found by me varies somewhat from the type, make- 

 ing this identification doubtful, especially as the species has not been 

 found hitherto except in the fossil deposit at Oamaru, New Zealand 



If we consider it merely a wide variety of S. calif ornicus, the view 

 originally taken by Grove and Sturt, its presence in the Philippine 

 Islands, where S. calif ornicus is abundant, would be more easily under- 

 stood. I have felt it to be worth while to illustrate here the Phil- 

 ippine Islands form which agrees with Schmidt's figure as to its pecu- 

 liar border and the large, irregularly scattered beads, the latter, how- 

 ever, being more abundant in my specimen. 



STICTODISCUS PARALLELUS (Greville) Grove and Sturt 



(Schmidt, Atlas, pi. 75, fig. 13; pi. 76, figs. 15-16; pi. 131, fig. 9.) 



The last reference above i; th prevailing form in the Philippine 

 Islands, called by Grove nd Sturt variety gibbosa. 



STICTODISCUS RADFORDIANUS Castracane 



See Trigonium radfordianum (Castracane) Mann. 



STICTODISCUS RADIATUS Castracane 



(Castracane, Chall. Exp., pi. 1, fig. 1.) 



Hardly separable from S. californicus. It seems to be peculiar to 

 the Philippine Islands, the original type having been found there at 

 Zebu. 



STICTODISCUS SIMPLEX A. Schmidt 



(Schmidt, Atlas, pi. 74, fig. 11.) 



Found originally in San Francisco Bay, Calif. The single small 

 but evident bead at the center of the valve appears in the specimens 

 found by me and seems to be constant. 



STICTODISCUS VARIANS Castracane 



(Castracane, Chall. Exp., p. 120, pi. 17, fig. 7.) 



A review of the comments made under the different species of Stic- 

 todiscus here listed makes it evident that, although the genus itself 

 is well defined, its species are usually inconstant, a large part of them 

 seeming to be only variations of S. californicus, a species which 

 unquestionably shows extreme variability. 



Genus STOSCHIA Janisch (invalid) 



STOSCHIA ADMIRABILIS Janisch 



See Coscinodiscus reniformis Castracane. 



