128 



EDWAKDS, ON AMERICAN DIATOM ACE.*:. 



or have been found to be synonymous with already described 

 species, and should be designated thus : — 



Actinocyclus bioctonarius, Ehr. 

 Actinoptyclius senarius, Ehr. 

 Eupodiscus Rogersii, Ehr. 

 Piunularia didyma, Ehr. 



„ lyra, Ehr. 

 Raphoneis rhombus, Ehr. 

 Stauroptera aspera, Ehr. 

 Surirella circumstuta, B. 

 Gailliouella sulcata, Ehr. 



Coscinodiscus actinoptyclius, Edw. 

 Actinophoenia splendens, Shad. 

 Eupodiscus argus, Ehr. 

 Navicula didyma, A". 



„ lya, K. 

 Doryphora amphiccros, K. 

 Stauroneis pulchella, W. S. 

 Tryblionella scutcllum, IF. S. 

 Orthosira marina, Ehr. 



Actiniseus sirius, Ehr., and Dictyocha fibula, Ehr., are 

 neither of them Diatoms, and are most probably portions of 

 the skeleton of a Holothuria. 



Some two years back, I received from a friend residing at 

 Charleston some of the so-called black " pluff " mud, taken 

 from between watermarks, and which I found to be extremely 

 rich in Diatomaceous forms. The following species were 

 observed : — 



Actinocyclus undulatus, Ehr. 

 Actinophoenia splendens, Shad. 

 Auliscus cselatus, B. 

 „ pruinosus, B. 

 „ punctatus, B. 

 Biddulphia rhombus, W. S. 



„ aurita, Bred. 



Campylodiscus cribrosus, W. S. 

 Cocconeis scutellum, Ehr. 

 Coscinodiscus actinoptyclius. Edw. 



„ eccentricus, Ehr. 



„ lineatus, Ehr. 



,, oculus-iridis, Ehr. 



,, radiatus, Ehr. 



,, subtilis, Ehr. 



Epithemia ITyndmanii, W. S. 



„ musculus, K. 

 Navicula didyma, K. 



* „ maculata, n. sp. 



* „ pennagua, n. sp. 

 Nitzschia scalaris, W. S. 

 Pleurosigma angulata, W.S. 

 Triceratium altemans, B. 



favus, Ehr. 

 punctatum, T. B. 

 Tryblionella scutellum, W S. 

 „ punctata, W. S. 



The Navicula sigma, Ehr., of Bailey's list, is most probably 

 synonymous with the Pleurosigma angulata, W. S., of mine. 

 Those species marked with an asterisk (*) are new, and are 

 characterised as follows : — 



Navicula maculata, n. sp. = Stauroneis maculata, B., 1850. 



" Lanceolate or elliptical ; ends slightly produced and 

 rounded; surface punctato-striate, with a Large smooth cen- 

 tral spacfe." Bailey. To this description 1 have to add the 

 following measurements : Length '055 in. ; breadth '00216 in. ; 

 striae coarsely moniliform, 12 in. '001 in. 

 Navicula perrmgna, n. sp.^Pinnularia pemwffna, B., 1850. 



" Large, lanceolate on the ventral faces, with punctato- 

 striate marginal bands, and a broad, smooth central stripe; 



