518 Mr. C. Mereschkowsky on Californian Diatoms. - 
235. Asteromphalus elegans, Grev. (Diatomeentaf. pl. xxi. 
fig. 6). Calif. guano. [Gv.] 
236. Asteromphalus flabellatus, Grev. (Diatomeentaf. pl. xxi. 
figs. 4,5). Calif. guano. [Gv.] 
237. Asteromphalus heptactis (Bréb.), Ralfs (Spatangidium 
Ralfsianum). Calif. guano. [Gv.] 
238, Arachnoidiscus Ehrenbergii, Bail. San Pedro, rather 
rare; Northern California, common. [M.] 
239. Arachnoidiscus ornatus, Ehr. San Pedro, rather com- 
mon. [M.] 
240. Stictodiscus californicus, Grev. Calif. guano; San 
Pedro, not rare. [Gv., M.] 
241. Actinocyclus Ehrenbergii, Ralfs. San Pedro, rare. [M.] 
242. Actinocyclus subtilis (Greg.), Ralfs. Monterey, com- 
mon. [M.] 
243. Coscinodiscus curvatulus, Grun. Northern California, 
not very rare. [M.] 
244. Coscinodiscus excentricus, Ehr. Northern Pacific, rather 
rare... [A.,,.M.] 
245. Coscinodiscus gigas, Ehr. San Pedro, rare; Northern 
California, very common. [M.] 
246. Coscinodiscus lineatus, var. leptopus,Grun. San Pedro, 
rare; Northern California, rather rare. [M.] 
247. Coscinodiscus nitidus, Greg. San Pedro, rare. [M.] 
248. Coscinodiscus nitidus, var. radiata, Mer. San Pedro, 
rare. [M.] 
249, Coscinodiscus radiatus, Hhr. San Pedro, very common ; 
Northern California, not rare. [M.] 
250. Coscinodiscus radiatus, var. centralis (Hhr.), Rattr. San 
Pedro, rare. [M.] 
251. Coscinodiscus radiatus, var. concinna, W. Sm. Northern 
California, rather rare. [M.] 
252. Coscinodiscus radiatus, var. oculus iridis, Khr. San 
Pedro, rare; Northern California, not rare. [M.] 
253. Coscinodiscus subtilis (Hhr.?), Grun. San Pedro, not 
rare ; Northern California, rather common. [M.] 
