232 Transactions of the Royal Microscopical Society. 
II. — Biatomacem in Slides of Santa Monica Deposit. 
By F. KiTTON, Hon. F.K.M.S. 
{Read hefore the Royal Microscopical Society, October 4, 1876.) 
The Santa Monica Diatom Deposit. 
A SAMPLE of this deposit was presented to the Society by 
H. Hanks, Esq., of San Francisco, and being examined by 
F. Kitton, Esq., F.K.M.S., was reported upon by him as follows : 
No. 1. Eui)odiscus Bogersii. — This specimen shows the "furrow" 
much more distinctly than usual ; it is, however, present in the 
fossil forms from the New Nottingham (Bermuda) deposit. A. 
careful examination of a series of valves of E. Argus * shows that 
the " furrow," although much less marked than in the preceding 
species, is present also in that form. If the "furrow" is of any 
generic value the above-named forms should be referred to the 
Aulacodisci. This species is rare in the Santa Monica deposit. 
No. 2. This slide contains the following forms : Stictodiscus 
Californicus, three valves ; Arachnoidiscus Ehrenbergii, three 
valves ; Actinoptychus, sp. ? one valve ; Triceratium Arcticum, three 
and four angled ; Kaphoneis, sp. ? one valve ; Auliscus Hard- 
manianus, one valve ; Coscinodiscus radiatus (according to Schmidt 
this is C. radiatus), var. minor of Ehrenberg ; Navicula excavata, 
Schmidt. ? var. 
No. 3. Aulacodiscus pulcher, one valve ; Arachnoidiscus Ehren- 
bergii, four valves ; Stictodiscus Californicus, three valves ; Cos- 
cinodiscus radiatus, as above ; Actinoptychus Griindleri, Schmidt 
(very fine and perfect) ; Auliscus reticulatus ? ; Navicula prsetexta. 
No. 4. Arachnoidiscus and Stictodiscus, as in preceding shdes ; 
Navicula prsetexta ; Asteromphalus variabilis. 
No. 5. Arachnoidiscus and Stictodiscus, as before ; Triceratium 
Montereyii ; Actinoptychus Griindleri ; Aulacodiscus pulcher ; 
Actinocyclus interpunctatus ; Cocconeis splendida ; Navicula spec- 
tabilis. 
No. 6. Actinoptychus, probably a new species. 
No. 7. Auliscus Hardmanianus, perfect valves. 
No. 8. Eupodiscus oculatus. 
No. 9. Cyclotella operculata, var. perhaps identical with Ehren- 
berg's Melosira sol (figured in the ' Microgeologie '). 
I did not find in the Sta. Monica deposit sent me any new species 
excepting No. 6. A larger quantity might perhaps yield some new 
ones. 
No. 9 is from the Madrid (?) deposit sent to me for examination 
by the Society. 
* E. Argus has similar markings, and is perhaps only a variety of E. Bogersii. 
