elongatum, at the period of its perfect developement.
Fig. 4. The same in a younger condition. Fig. 6. The
same with the frustules thrown back. Fig. 5. The same,
var. cuneatum.— Figs. 7 and 8. States of Diatoma virescens ?
Fig. 9. Tabellaria flocculosum, in an early period of its
growth. Fig. 10. The same in a more advanced period
of its developement.
P L A T F XCV.
Fig. 1. Fragtlaria pectinalis, showing the stria? on the anterior
surface of the frustules. Fig. 2. The same. Fig. 3.
Showing the oblique division of the frustules which occasionally
takes place. Fig. 4. An interesting condition of
the same: a a, end view of frustules of the species in its
ordinary state; b, the same of frustules of the variety
/3 undulata.— Fig. 5. Filaments o i Fragilaria hyemalis: a,
front view; b, end view of frustules of the same. Fig. 6.
Fragilaria rhabdosoma; a, front view; 5,end view.—Figs. 7
and 8. Successive stages of the developement of Diatoma
virescens; a a a, front views ; b b, end views of frustules of
the same.
P L A T E X CV I.
Figs. 1 to 4. Portions of Meridion circulare of different ages.
Fig. 5. Frustules of a condition of the same. Fig. 6.; a a,
front view of two frustules of the same: b b, side view of
the same. Figs. 7 and 8. Fronds of Meridion constrictum.
Fig. 9 .: a c, front view of two frustules of the same: b d,
end view of the same. — Fig. 10. Tabellaria fenestratum;
a, front view; b, end view of a frustule of the same. —
Fig. 11. Tabellaria flocculosum in the most advanced stage
of its developement: a front view; b, end view of a frustule
of the same.
P L A T E X C V II.
Fig. 1. Exilaria capitata.— Fig. 2. Exilaria Ulna.— Fig. 3.
Exilaria fascicolata. — F ig. 4. Exilaria lunaris. — Fig. 5.
Eunotia arcus: a, front view ; b, side view. — Fig. 6.
Eunotia diodon: a, front view ; b, side view. — Fig. 7. E u notia
triodon: a, front view ; b, side view. — Fig. 8. E u notia
tetraodon: a, front view; b, side v iew ; c, oblique
view.
P L A T E X C V I II .
Fig. 1. Gomplionema geminatum. — Fig. 2. Gomplwnema
truncatum.
P L A T E X C IX .
Fig. 1. Gomphonema acuminatum. — Fig. 2. Gomplionema
dichotomum.
P L A T E C.
Fig. 1. Gomplionema cristatum.— Fig. 2. Gomplionema Berhe-
leyi. ■— Fig. 3. Gomplionema minutissimum. — Fig. 4. Ach-
nantlies minutissima. — Fig. 5. Achnanthes exilis 9 — Fig. 6.
Cymbella A r cu s : a, front view ; b, side view’. — Fig. 7.
Cymbella turgida : a, a, front view; b, side view. — Fig. 8.
Cymbella zebra: a, front view ; b, side view. — Fig. 9.
Podosplienia ? ocellatum. — Fig. 10. Encyonema prostratum.
P L A T E CL
Fig. 1. Cocconema lanceolatum. — Fig. 2. Cocconema cym-
biforme. — Fig. 3. Cocconema Cistula.— Fig. 4. Cocconema
ventricosum.
P L A T E CIL
Fig. 1. Surirella biseriata; a, front view; b, side view.—
Fig. 2. : a, b, c. Frustulia viridis. — Fig. 3. Sphinctoeystis
librilis ; a, front view ; b, side view. —■ Fig. 4. Navicula ?
yibba. — Fig. 5. Navicula amphisbana : a, front view ; b,
side view. -— Fig. 6. Navicula platystoma. — Fig. 7. Navicula
? nodosa. — Fig. 8. Aulacocystis pellucida. — Fig. 9.
Navicula phcenicenteron. — Fig. 10. Navicula Paha. —