78 
LaudeRj 071 Marine Diatomacece. 
C."^ variety of C. Lauderi? Filaments larger, with 
abruptly constricted fenestras, and long, slightly curved 
awns; lateral view oval (fig. 3). Breadth of frustule from 
0 10 0 ^^ 6 0 0 • 
C. affine, n. sp. Filaments as in C. Lauderi, but with the 
terminal awns incurved and stouter than the rest ; sporangia 
with unequal, convex, hirsute valves (fig. 5). 
Occasionally some of the intermediate awns are enlarged 
similar to the terminal ones. C. affine differs from C. Lau- 
deri, principally in its sporangia, which are not constricted, 
have more delicate spines, and the lesser valve is siliceous 
and permanent. Breadth of frustule, tttW- 
C. compressa, n. sp. Filaments with broad, constricted 
fenestra, and awns arising from a little within the angles ; 
lateral view of valves compressed oval (fig. 6) . 
Filaments straight, here and there having the awns of con- 
tiguous valves much longer and stouter than the intermediate 
ones, and conspicuously beaded and flexuose. Sporangia un- 
known. Breadth, toVo'' j length of awn, about tto-''* 
^■^ Awns cellulose. 
C. cellulosa, n. sp. Awns cellulose, varying in size and 
length (fig. 12). 
Filaments straight, with oval, constricted fenestra, quad- 
rangular awns, having regular oval or quadrangular depres- 
sions over their whole surface, the terminal awns stouter and 
shorter than the others. Frustule quadrangular, with a 
curved line running across from the insertion of one awn to 
that of the other, and which is apparently the line of junction 
between the hoop and the valve, the latter, from its slightly 
turgid shape, being seen in the front view ; lateral view oval. 
Breadth of frustule, from -nnro'' -rfo'' 
Awns spinous. Filaments usually stouter than in 
the preceding divisions. 
C boreali? Frustules quadrangular, with four-sided, 
stout, striated, and coarsely spinous awns, arising from the 
centre of the depressed valves (fig. 7) . 
I have only met with this species in single frustules. 
Awns iToW broad, about thirty times longer than broad, 
with spines arising in an alternate manner from the angles, 
those of upper valve recurved, and parallel with those of the 
* The form of the interstial foraminse differs so much from that of 0. 
Lauderi, that it is probably a distinct species, which we propose to name C. 
incisor. — J. E.ALFS. 
