KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. /8. w:o 5. 19 
Rutilaria Grev. 
1. Rutilaria recens Cu. N. Sp. 
Valve plane, elliptic or elongate with acute ends. It is covered with numerous 
scattered puncta, which sometimes are arranged in irregular lines. Besides these there 
are in the centre of the valve some more strongly marked puncta, and which seem to 
belong to another stratum of the valve. The margin has a row of puncta, which are, 
as may be seen in the F.V., short spines. In the F. V. the ends of the valve termi- 
nate in short processes. 
Length 0,037—0,11 mm. Breadth 0,02 mm. 
Pl. IV, fig. 57, a. *°°°/, (an abnorm specimen having no puncta on a part of the 
valve), b. 800) small specimen. 
Gallapagos Islands (Eugenie fixpy 
The genus Rutilaria established by Dr. GrevitLE, comprises only some few spe- 
cies, all fossil. These are R. Epsilon Grev., rare in Monterey stone, R. superba (and 
var.? ventricosa) Grev. and R. elliptica Grev. from Barbados. They all have the cu- 
rious markings in the centre of the valve, which are elevations above the level of the 
frustule, as is visible on the fig. 10, Pl. XI, T. Micr. Soc. Vol. XIV. In our recent 
species these markings are represented only by the strongly marked puncta. From 
GREVILLE’s fig. of the F. V. of &. elliptica and R. superba it is evident that the valve 
is plane and that its apices are produced into processes, and farther that the margins 
of the frustule are bounded with a row af sete, exactly as in our species. 
The position of Rutilaria is somewhat uncertain. GrevittE has pointed out its 
relationship to Nitzschia and Fragilariee. Prof. Hamiron Smiru places it among the 
Melosire. It has however no real affinity with Nitzschia or Melosire, but is very 
nearly allied to the genus Cymatosira Grun., of which the only known species C. Lo- 
renziana GRuN. has also marginal bristles. The Cymatosira is without doubt nearly 
related to Dimerogramma. 
Mr. Kirron writes to me in a letter about a new species of Rutilaria from the 
Californian deposits, Rut. obesum Grev. Mpt. The valve has 3 inflations, the central 
being the largest; the apices are shortly cuneate; one third of the area is smooth, the 
remainder distinctly covered with irregular markings. The central nodule consists of 
a nebulous circular spot, upon which is placed a short spiral (?) ring. Margin distinctly 
punctate. Mr. Kirron has seen about half a dozen specimens of this species, all 
frustles, and in no case was he able to separate the valves. I crushing partially one 
specimen in balsam, he observed that the nebulous central nodule was the base of a 
siliceous isthmus, connecting the two valves. 
