Several years ago I received through Professor $. Loven from the Swedish State 
Museum some samples af shellsand and mud, which had been collected during the ex- 
pedition of the Roy. Swedish Fregaté Eugenie 1851—53 on the Gallapagos Islands, 
Honolulu, Port Jackson etc. On ‘examining these samples, as well as many others, 
received from various friends and correspondents, I found a number of diatoms, which 
seems to me to be entirely new to science or at least of interest. Especially am I in- 
debted to Dr. SépERLUND for some very rich materials from the Mediterranean Sea and 
the Balearic Islets, to Mr. Curistran Fesicer, the wellknown diatomist of Wilmington, 
Delaware, Mr. Hauck of Triest, Prof. Beracren, Dr. O. Norpstept and others for va- 
rious interesting gatherings. Mr. Grunow of Vienna has kindly helped me in preparing 
this paper and assisted me in many cases of uncertainity, and for which I here take 
the liberty of tendering him my best thanks. 
Mastogloia Tuwairzs. 
1. M. panduriformis Cu. N. Sp. 
Valve panduriform with cuneate ends. Margin with somewhat distant loculi, ex- 
cept in the middle, on both sides of the central nodule, where they are wanting or 
indiscernible. The surface of the valve is covered with small, irregularly scattered 
puncta and very fine (20 in 0,01 mm.), parallel, punctate striw. These striw, which are 
not strongly marked, cover the whole valve, except a small area, round the straight 
median line and central nodule. Terminal nodules turned in opposite directions. 
Length 0,0975 mm. Breadth 0,027 mm. at the constriction 0,0195 mm. 
Gallapagos Islands (Eugenie Exp.) Very rare. 
Phe de figs Te is 
The outline of the frustule, the few and large loculi as well as its peculiar 
structure destinguishes this fine form from all previously known species. Its nearest 
allies are the Navicule or Mastogloix, forming A. Scumrpts section Pseudodiploneis, 
N. marginata Lewis, N. strangulata Gruv., Mastogl.? reticulata Grun. 
