334 Notes on New Species 



Actinocyclus. I have therefore marked the genus as doubt- 

 ful, although not originally considered so. Even in the 

 identical specimen recorded first as Actinocyclus and then 

 as Coscinodiscus tenuis., I think I have distinctly seen at 

 least two processes, as in Eupodiscus. There are several 

 varieties of Eupodiscus in this locality, one nearly allied to 

 E. radiatus, but with very short processes. Many of them 

 resemble Coscinodisci. 



Fig. 16. Navicula septenaria, Bail., nov. sp. Minute, 

 in general outline rhombic; sides undulated, producing 

 seven wide parts and six constrictions ; central nodule and 

 line distinct ; striae wanting or obscure. 



Hab. Para City. 



This form, which is possibly a fresh-water species, would 

 be easily mistaken with moderate powers for some form of 

 Spong-iolites ; but with the highest powers it is exceed- 

 ingly regular and graceful, the nodule is distinct, and the 

 median line well marked. The only specimen seen is 

 opaque and porcelaneous, showing with the highest pow- 

 ers no signs of striae. I think, however, there can be no 

 doubt of its naviculoid nature. 



Fig. 17. Pleurosigma , nov. sp. ? This would 



seem to be a variety of P. injlatum of Shadbolt. I have 

 been unable to find the original specimen, and can there- 

 fore only trust to the outline as originally drawn. Sev- 

 eral varieties of this genus occur here. 



Figs. 18 and 19. Hyalodiscus . This possibly 



may be a variety of H. Iccvis, from the description of which 

 it diiiers only in size, but from one poor specimen I have 

 been unable to ascertain its specific cliaracters. It is quite 

 small, the markings are coarse compared with those of 

 H. subtilis or H. Californicus, and the suture irregular and 

 jagged. The rim is quite broad, and the valves very con- 

 vex. The centre is densely granulate. Possibly it may 

 be some form of Podosira. 



