EET 
eee 
98 Sketch of the Infusoria of the family Bavillaria. 
8. Navicula ———. (PI. 2, fig. 18.) This figure represents a pam 
duriform species, very much contracted in the middle. It occurs in 
peat from a salt marsh near Stonington, Conn. 
4, Navicula (Pl. 2, fig. 19.) _ This species occurs with the 
last, and is nexhans a state of it resulting from its complete spontaneous 
division into two individuals by the contraction at the middle. 
5. Navicula (PL 2, fig. 20.) This sesembles the preced- 
ing very much, but is a fresh-water species, ee ae in ponds neat 
West Point, also in streams in irginia. 
6. Navicula? striatula. (PI. 2, fig. 21, a, .) 1 refer to this genus 
with much hesitation the very elegant wads interesting species shown by 
fig. 21 a, b. It is easily known by a set of peculiar and beautiful un- 
dubatinsg ridges, represented in the figure, and which giv wre. margin 
of the form a ruffled appearance, in whatever position they are ob- 
served. One of the faces (a) is lanceolate, the other (b) is somewhat 
wedgeform, with both ends obtusely truncate. The lanceolate face 
shows a set of fine lines apparently proceeding from the ritlges above 
referred to, and reaching nearly to the middle line of the face. I have 
sometimes seen two individuals united laterally by their lanceolate 
faces, producing a very beautiful form. All the individuals which I 
have seen, have been free, without pedicel, and when living, their spon- 
taneous motions were very distinct. I have found it in a living state in 
fresh-water ponds and streams near West Point, also in Mountain Run, 
near Culpepper Court House, in Virginia; and I detected it in a fossil 
state among other fossil infusoria from Bridgewater, Mass. (See figs. 
6 and 7, Pl. 20, of Hitchcock’s Final Report on Geology of Massa- 
chusetts. 
In Pritchard’s History of Infusoria, I find two figures repre- 
senting N. striatula, which leave no doubt that ours is the same 
species. - See Hist. Inf. Pl. 3, fig. 137, 138.)° The following 
sting remarks with regard to the organs of panmeemnese in 
this genus, are also taken from this work. 
“In the small pools left by ebb of the tide near Conntuavettp 
Dr. Ehrenberg remarked numerous little bodies, apparently simi- 
Jar to Navicula (Surirella) elegans and N. striatula, but which 
from their comparatively very great size and structure of loriea, 
were easily distinguishable from the latter upon closer examina- 
tion. One of these ribbed glass-like creatures was, besides its 
size, remarkable Ase its great mobility, and Dr. E. was ena 
to investigate its S sys "locomotion much more satisfactorily 
ad hithe >in any of the genus. ‘This organ he 
it, both in form and size, to what he had 
ate 
“hal 
