26 P. T. CLEVE, ON SOME NEW DIATOMS. 



short rows, 5 in 0,01 mm. In the angles the puncta are much smaller and form fine 

 branching lines. 



Distance between angles 0,0975 mm. 

 Pl. VI, tig. 72, ""/,. 



Gallapagos Islands rare (Eugenie Exp.). 



9. Triceratiuni margaritiferum, Cl. N. Sp. 



Valve quadrangular with concave sides and rounded angles, without processes. 

 Surtace probably plane. Structure tolerably coarse granules arranged near the margins 

 in short lines, smaller in the angles, rare and scattered in the middle. 



Diam. 0,05 mm. 



Pl. VI, tig. 76, ^"7i. 



Gallapagos Islands rare (Eugenie Exp.). 



Cliaetoceros Ehb. 



1. Chcetoceros Dichceta Ehb. = C. remotus Cl. et Grun. 



This form has already been described in Cl. et Grun. Aret. Diat. p. 119 and is 

 to be found in most siides of Cl. et Moll. Diat. N:o 125. 

 Pl. VI, tig. 77, '''I,. 



Antarctic Ocean (Challenger Exp.). 



Rhizosolenia Ehb. 



1. Rhizosolenia {alata var.?) gracillima Cl. 



Extremely long and slender, measuring 0,5 — 0,7 mm. in length and only 0,006 

 mm. in breadth. The beaks are almost straight, provided with pocket-like impressions. 

 The zig-zag markings on the connecting membrane are very indistinct. The frustule 

 is extremely hyaline, having no colour in diy state. No structai"e has been seen. 

 Pl. vi, tig. 78, "»7i. 



West coast of Sweeden, Lysekil, freely tioting on the surface of the sea (July 

 1877 by P. T. Cleve). 



Another slender species, characterized by its coarse, of puncta composed striaä, 

 Rh. Shrubsolii Cl. N. Sp., occurs in the Atlantic Ocean between Iceland and Green- 

 land. It was recently found in great abundance on the sui'face of the sea near the 

 island of Sheppey by Mr. 8hrubsole. 



