512 Mr. CG. Mereschkowsky on Californian Diatoms. 
the Californian form differs from the latter by its greater 
size, attaining O°l mm., usually 0-07-0'085 mm. (the type 
varies from 0:035-0:088 mm., average of thirty-three cases 
0:054 mm.), and by the eudochrome, which is always com- 
posed of numerous moderately elongate elliptic granules, 
while in the Mediterranean form they are usually very elon- 
gate, bacilliform, and not numerous. I give no name to 
this variety, as it requires further examination. 
165. Licmophora Thumii, Mer. (PI. V. fig. 7.) Monterey, 
common. [M.] 
Valve of medium breadth, strongly clavate, slightly ar- 
cuate and asymmetrical, rarely symmetrical; upper part 
inflated, attenuated towards the superior apex, which is broad, 
truncate, abruptly attenuated at the superior quarter, be- 
coming narrow and almost linear, inferior apex slightly 
inflated. Pseudoraphe broad, very distinct; striz 16-17 in 
0-01 mm., at the lower end as well as in the middle. Girdle- 
face cuneate, with rather thick outlines, upper angles sub- 
acute. Septa deep (average 0016 mm.), slightly arcuate, thin 
below the septal puncta, thick above them. Length 0:098- 
0°188 mm., breadth of the valve 0'0115-0:0180 mm. 
It is to Mr. Ed. Thum of Leipzig, the celebrated mounter 
of diatoms, who on many occasions assisted mein my studies, 
that I dedicate this species. It has no close relation te any 
other. 
166. Eunotogramma, sp.? (PI. V. figs. 24-27.) San Pedro, 
rare; Hawaii, rare. [M.] 
I give the figures of a species of Hunotogramma which I 
have met many times, and which, for lack of necessary books, 
Iam unable to determine. The strize are sometimes fine, 
invisible with an ordinary magnitying-power (figs. 26, 27), 
sometimes distinct (figs. 24, 25), about 9 or 10 in 0:01 mm. 
Length 0:0175-0:023 mm., breadth of the girdle-face 0-011- 
0°013 mm., breadth of the valve about 0-007-0:008 mm. 
167. Raphoneis amphiceros, var. rhombica, Grun. San Pedro, 
rare. [M.] 
168. Opephora pacifica (Grun.), Petit. San Pedro, Mon- 
tcrey, common. [M.] 
169. Clavicula recens, Mer. Northern California, very rare. 
[M.] 
See my paper “ On Polynesian Diatoms,” chapter iv. 
170. Fragilaria (striatula, var. ?) californica, Grun. [G.] 
