Mr. C. Mereschkowsky on Californian Diatoms. 509 
apex, which is broad and rounded * ; margins straight, superior 
apex broadly rounded. Pseudoraphe indefinite; strive very 
fine, not less than 24-25 in 0°01 mm. Girdle-face narrow, 
cuneate, with rather delicate margins, upper angles rounded. 
Septa superficial, very thin, straight, septal puncta small, 
strongly marginal. Endochrome granular. Length 0:031- 
0-041 mm., breadth of the girdle-face 0°0077-0:0125 mm., 
breadth of the valve 0:010-0:011 mm. 
This variety differs from the type species, into which it 
gradually passes, by its broader valves and the more delicate 
appearance of the frustule. The breadth of the valves of 
L. dubia is about 0:009 mm., sometimes only 0:006 mm, 
{and even 0:0053 mm.), while here they are never below 
0-OL mm., and their form is somewhat different, being more 
ovoid. 
158. Licmophora flabellata (Carm.), Agardh. Common. [M.] 
159. Licmophora flabellata, var. parva, Mer. (Pl. V. 
figs. 12-14.) San Pedro, not rare; Monterey, very 
common. [M.] 
I have quite a number of slides containing L. flabellata 
from the Black Sea, the Adriatic, the Mediterranean, the 
Californian coast, &c., in which this species, although 
greatly varying in size, is never represented by specimens 
below 07117 mm., varying from 0°117 to 0-437 mm. In one 
gathering from Monterey, however, I found in great number 
a small form varying from 0:064 to 0°146 mm., usually being 
about 0°075-0°1 mm., in which larger individuals are very 
scarce, and this same form frequently occurs also in several 
gatherings from San Pedro and in one from Sumatra. ‘These 
facts prove undoubtedly that such forms cannot be considered 
merely as small-sized individuals of L. flabellata, but rather 
represent a separate variety, peculiar as it seems to the Pacific 
and Indian Oceans. 
The form of the valve, in the smaller specimens at least, 
is also somewhat different and the girdle-face is broader 
and more cuneate. I give here a series of individual 
measurements :— 
Length : 0:064 0:068 0:068 0:072 0-082 0-083 0:090 
Breadth of the frust.: 0:020 0°025 0°031 x 0-019 0:024 0:027 
0:094 0:098 0:100 0:127 0-146 
0-021 0-020 0-031 x — 0-020" 
Breadth of the valve 0°007-0:008 mm. 
* Fig. 10 has been represented by the engraver as being slightly asym- 
metrical, which is not the case. The upper margin of fig. 11 ought to be 
straight. 
