Gomphonema Americana Kestoek 
eee lanceolatum Thylacium ossiculum 
Py nasutum “ semiorbiculare 
* undulatum f te 
Himantidum gracile 
Navicula Americana Achnanthes pactrypus 
amphigomphus 
amphioxys 
Bacterium 
oc sl licata 
“ — Sillimanorum 
oi tumidula 
Staurosira construens 
: pinnata © 
Tabellaria amphilepta 
5: nodosa 
- biceps 
espe ramosa_ 
Actinocyclus hexapterus_. 
Cocconeis oceanica 
Dictyocha panduriformis 
splendens 
Echinella moniligera 
Fragillaria catena 
“cc 1 
innata 
Gomphonema subtile 
Grammatophora Mexicana 
Navicula Campylodiscus 
“© bicarinata 
“  erucigera 
© * et 
“reticulata 
Podosira moniliformis 
yee capitata 
clara 
“ Noviant 
“ 
Paes 
- Globulus porosus 
Spirulina vivipar 
Biloculina tenella 
extilaria plicata 
serpe 
pe ts ta can Be added a great number both of recent and fossil 
3 
wee 
been favored Sapa elelapoye a G. a Eag,, of the. Dediek 
legation at Washington, with an early copy of a paper read by Mr. 
Weeks, March 15th, 1842, before the London Electrical Society, on 
the Acarus Crossi. It is now about four years since the scientific world 
was excited in an unusual degree by the Voltaic experiments of Mr. 
Andrew Crosse, in which Acari appeared on and about the 
and subject of experiment, during a long continued electrical action, 
The general belief seems to have been, that in spite of all precautions, 
