33 
Notes on J)iatomacb2e found near Gambia^ O. By Professor 
Hamilton L. Smitii_, of Kenyon College^ Gambia, O. 
(Communicated by E. G. Lobb, Esq. Head Nov. 15, 1859.) 
The few slides sent herewith may be acceptable to the 
Society as representatives of aquatic genera and species 
common in the interior of the United States. The slides are 
numbered at the right-hand top ; they are mostly balsam 
mounted, a few are mounted dry, and a few in distilled 
water. 
1. Meridion circulare. — Exceedingly abundant, and always 
found attached to the same conferva ; it has occurred also 
with very long stipes, say three or four times the length of 
frustule. Generally, quick -running streams. 
2. Gomphonema anomalum, n. sp. — This Gomp., to which 
I have attached the provisional name ^' anomaium,^^ was found 
conjugating, single frustules producing single sporangia, 
contrary to the hitherto observed Gomphonema. The spe- 
cimen w^as prepared by burning on the glass cover. It is 
same as No. 32. 
3. Gomphonema ovatum, n. sp. — Found conjugating (same 
as No. 16), prepared by burning on the cover ; double sp. I 
have given to this the provisional name " ovatum." 
4. Stauroneis. — Supposed to be sporangia of Phmne- 
centera ; may be new, however, it is much coarser, and varies 
somewhat in outline. 
5. Surirella, &c. 
6. Diatoma tenue. — Prepared by burning. 
7. Cocconema cymbiforme. — Found conjugating. (See 
after No. 40.) 
8. Gomphonema dichotomum, &c. 
9. Gomphonema sarcophagus ? Greg. 
10. Eunotia, &c. 
11. Collotonema vulgar e. — This is the diatom most abun- 
dant here, and is found in almost every stream. Strise about 
77 in -001" ; prepared by burning. It sometimes forms thick 
skins of several layers, and when placed in quiet water throws 
out little tufts or "papillse" towards the light, almost colourless 
except at their summit, which becomes almost black by the 
aggregated diatoms; these papillse are from \ to 4- in. in 
length. No. 22 is the same in fluid, shoAving the curious 
encysting which sometimes occurs. This encysting is quite 
common among the diatoms, but has no relation to con- 
jugation, as supposed by Smith, in S. B. D. (remarks on 
>Sf. radians). No. 21, ^. capltata, will be found to contain 
