1888 - 89 .] Mr John Rattray on the Genus Coscinodiscus, 601 
C. parma, Bail. According to Prof. H. L. Smith (Lens, 1872, 
p. 232), who has examined the Bailey Collection bequeathed to the 
Boston Society of Natural History, this is Stidodiscus californicus , 
Grev. (Trans. Micr. Soc. Lond., 1861, p. 79, pi. x. fig. 1), of which 
Bailey’s Triceratium parma is a triangular form. 
C. pyxidicula, Kiitz. (Sp. Alg., p. 126) is Pyxidieula 
Coscinodiscus, Ehrb. (Mon. Ber. Ak., 1841, p. 85), and belongs to 
Craspedodiscus, approaching Cr. elegans, Ehrb. 
C. cruciatus, Kiitz. (Bacil., p. 132, pi. xxviii. fig. 10), belongs to 
Pyxidicula. Specimens have been procured from Vera Cruz and 
Richmond, Va. 
C. pyxis, Ehrb. (Mikrog., pi. xxxiii. 13. fig. 3*), is perhaps a 
Melosira. It cannot he united to Coscinodiscus. 
C. quindenarius. This name is erroneously quoted in Habir- 
shaw’s Cat. Diat., 2nd ed., § Coscinodiscus,' for Actinocyclus 
quindenarius, Ehrb. (Mikrog., pi. xxi. fig. 17). 
C.fuscus, Norman (Trans. Micr. Soc, Lond., 1861, p. 7, pi. ii. fig. 
3) is Actinocyclus Ralfsii, not A.Barklyi, nor Adinoptychus Barklyi, 
as stated in Habirshaw’s Cat. Diat., 2nd ed., § Actinocyclus. 
C. grcecus, Kiitz. (Bacil., p. 132), was named Discoplea grceca by 
Ehrenherg (Mon. Ber. Ak., 1840, p. 208 ; Mikrog., pi. vi. 2. figs. 
1 a-c ). It is a Melosira or perhaps a Cyclotella. Specimens were 
found in Grecian marl. 
C. fiavicans, Ehrb. (Abh. Ber. Ak., 1841, p. 412, pi. i. 3. fig. 
17), has been defined as small, with delicate, non-radiate markings, 
being yellow by transmitted, and white by reflected light. Ralfs 
accepted this species (Pritch. Inf., p. 831) as belonging to 
Coscinodiscus ; to me it seems rather to he a Melosira. Simbirsk 
specimens, named C. fiavicans by Weisse (Bull. Ac. Imp. Sci. St 
Petersb., 1855, p. 276, pi. figs. 5 a, b), have coarse markings, and 
must be excluded. C. fiavicans ? Ehrb. (Mikrog., pi. xxxix. 2. figs. 
19, 20), are also distinct. Ehrenberg’s original specimens were from 
Peru and St Domingo. 
C. arafuscenis. O’Me., Quart. Jour. Micr. Sci., 1877, p. 463. — 
Diam. *375 mm. Central space small. Markings areolate, at the 
margin subhexagonal, diminishing in size towards the ends ; shorter, 
broader, and more robust than in C. craspedodiscus, O’Me., radial 
rows terminating some distance from the centre, but of more equal 
