514 Mr. C. Mereschkowsky on Callfornian Diatoms. 



liave observed * I have never seen such narrow elongated 

 valves as represented in fig. 23. It seems therefore advisable 

 to distinguish it as a separate variety. The puncta of the 

 valve are also much larger, and there is a punctum to be seen 

 at the bifurcation of tiie awns which does not exist in the 

 type sjiecies. General length 0'031 mm., length of the body 

 0-018 mm., breadth O'OO? mm. 



186. Chaetoceros lyra, iler. Northern California, very rare. 



See my paper " On Polynesian Diatoms," chapter iv. 



187. Rliizosolenia setigera, Brightw. San Pedro, rare. [M.] 

 Bristles very long, straight or arcuate, with a small bright 



punctum at the summit of the calyptra, or without it. Length 

 of the frustule (without the bristles) 0*1 mm. 



188. Rhizosolenia Stolterfothii, Per. San Pedro, rare. [M.] 



189. Rhizosolenia styliformis, Brightw. San Pedro, rare. 

 [M.] 



190. Skeletonema costatum (Grev.), CI. San Pedro, not 

 rare. [M.] 



191. Stephanopyxis ferox, Grev. San Pedro, rare; Calif, 

 guano. [Gv., M.] 



192. Stephanopyxis turgida, Grev. Calif, guano. [Gv.] 



193. Anaulus birostratiis, Grun, [V. II. J 



194. Biddulphia (Triceratium) alternans, var. tenuipunctata, 

 Mer. Northern California, very rare. [M] 



See my paper " On Polynesian Diatoms," chapter iv. 



195. Biddulpliia (Triceratium) antediluviana (Ehr.), V. H. 

 San Pedro, very rare. [M.] 



1 have seen only one specimen, which was almost identical 

 with the figure of Brightwell representing Amphitetras tessel- 

 lata t, and could therefore be determined as well as B. tessel- 

 lata. I fail, however, to see any difference between this latter 

 species and B. antediluviana, except in the alveoli of the first 

 species being less coarse (which is also the case in the specimen 

 from San Pedro) and the marginsof the valve less concave than 

 in the second one, although in this regard B. antediluviana 



• I have given a figure of C'h. incurvus in my paper " Note on 

 Diatoms from Chincha Guano," in Ann. & Mag. Nat. Hist., November 



I'.iOO. 



t ' Diatomeentafelu zusammengestellt fiir einige Ireuude,' pi. iii. 



fig. 11. 



