878 



SYSTEMATIC HISTORY OF THE INFUSORIA. 



tudinal line and nodules, and denticulate 

 sti'iae. 



C. Bremii (Nag.). — Pulvinate ; valves 

 slender, sublunate, with attenuated ends 

 and obtuse apices; striae very fine.' 

 KSA. p. 890. Eocks in streams. Switzer- 

 land. Large; stipes long, articulated; 

 frustules in front view lanceolate. 



C. cornutum (E.). — Valves slender ; 

 lunate, gradually tapering into long ends, 

 with obtuse apices ; venter concave, gra- 

 dually tumid at its middle. EM. pi. 15 a. 

 f. 94. America, Berlin. Lough Mourne 

 deposit. Large ; differs from C. lanceo- 

 latum in its more slender and tapering 

 form. 



C. Mexicammi (E.). — Stout; valves 

 lunate, with obtuse, slightly produced 

 ends ; ventral margiu slightly tumid ; 

 dorsum very convex ; striae 18 in 

 1-1152", distinctlv and elegantlv granu- 

 lose. EM. pi. 33. 7. f. 6, 7. 'Mexico. 

 Large. 1-206". 



C. Cistula (E.). — Valves lunate, with 

 very convex dorsum, and the concave 

 venter tumid at its centre ; stipes elon- 

 gated, filiform, subsimple. EI. t. 19. 

 f. 7 ; SBD. i. p. 76, pi. 23. f. 221. = Gom- 

 plionema semi-eUipticum, Ag CD. p. 33 ; 

 G. simplex, KSA. p. 37. Europe, Asia, 

 America. (x. 196-198.) 1-1150" to 

 1-430". Front view eUiptic-oblong, 

 with obtuse ends. 



C. GrcBcum (E.).— Habit of C. Cistula, 

 but with stronger and fewer striaB, 12 to 

 13 in 1-576". EKBA. 1840, p. 12. 

 Greece. 1-575". 



C ? biceps (E.). — Valves turg-id, semi- 

 oval, each ends in a flat and tumid mar- 

 gin, suddenly rostrate, obtuse ; sides 

 longitudinallv sulcate and ti'ansversely 

 sti'iate. ERBA. 1845, p. 362. Marine. 

 India. 1-576". Habit of C. Cistula. 



C. cymhiforme (Ag., E.). — Slender; 

 valves lunate, with somewhat obtuse 

 apices; venter straight or slightly con- 

 cave, with rather tumid centre ; stipes 

 intricate, forming a compact gelatinous 

 mass. EI. pi. 19. f. 8 ; SBD. i. p. 76, 

 pi. 33. f. 220. = Cymhella cymhiformis, 

 Ag CD. p. 10 ; Frustulia cijmhiformis, 

 KSA. Europe, Asia, America, (xii. 

 46.) 1-500" to 1-150". Transverse 

 striae 16 in 1-1200". Front view linear- 

 lanceolate, with truncate ends. It fomis 

 a brownish compact covering on rocks, 

 which is frequently of considerable 

 thickness and extent. 



C. ? ac^dum (E.).— Slender, slightly 

 cm-ved, smooth (?), with acute ends; 

 ventral margin slightly tumid in the 

 middle. EA. p. 123. Labrador, Falaise ?. 



Small ; habit of a curved Navicula am- 

 phioxys. 



C. tumiclum (Breb.). — Valves semilu- 

 nate, with obtuse, scarcely produced 

 ends ; ventral margin nearly straight ; 

 front view lanceolate, with truncate 

 apices. KSA. p. 60. France. Small. 

 1-576". Striae 16 in 1-1200". Stipes 

 elongated, filiform, simple. 



C. affine (K.). — ^^"alves lunate, with 

 very convex dorsum; stipes intricate. 

 KSA. p. 59. France. Minute. Resembles 

 Cymhella affinis, but is stipitate. 



C. gihhum (E.). — Valves semielliptic, 

 with trimcate, slightly produced apices ; 

 transverse striae verv delicate. KB. t. 6. 

 f. 6. Europe, Asia." (xm. 10.) 1-480". 

 jS sessile. Stipes obsolete. = Cymhella 

 Orsiniana, Rab D. p. 23. 



C. Arms (E.). — Semiluuate, with ob- 

 tuse apices ; dorsum very convex, venter 

 not gibbous. EM. several figures. Asia, 

 America, Lough Momne deposit. 



C. jmrvum (S.). — Valves lunate, with 

 subacute ends; ventral margin scarcely 

 gibbous ; front view nearly linear. SBD. 

 i. p. 76, pi. 23. f. 222. (vii. 47.) Cliff; 

 BeachvHead. Minute. -0009" to -0016". 

 Strict 21 in -001". 



C. Saxonicmn (Rab.). — Valves semi- 

 lunate, with acute ends ; ventral margin 

 straight or slightly concave ; dorsum very 

 convex ; sti'iae faint. Rab 1). p. 24, t. 10. 

 f. 11. Saxony. Minute. The front 

 xiew is figured as oblong, with tnmcate 

 ends, and the stipes dilated beneath the 

 frustule. 



C. Boechii (E.). — ^^^alves elongated, 

 lanceolate, with subacute apices ; front 

 \dew linear-lanceolate, obtuse ; striae ^Q 

 in 1-1200". E Inf. t. 19. f. 5. = Gomplm- 

 nema lanceolatum, Ag CD. p. 34; Don/- 

 phora Boeckii, SBD. i. p. 77, pi. 24. f. 223. 

 Marine. Europe. Large. 1-210" to 

 1-120. Stipes dichotomously divided. 

 (^^I. 48.) This species is no doubt 

 wrongly referred to Cocconema, since 

 both margins of the lateral valves are 

 symmetrical. We regard it as a stalked 

 Navicula, and find a central, though in- 

 conspicuous, nodule — a fact which, we 

 think, forbids it being placed in Dory- 

 phora as Professor Smith proposed. 



Species known to us only hy name. 



C. subtile (E.), Asia, America; C. 

 cingulatum (E.), Georgia; C. Javam- 

 cum (E.), Java; C. AraucanicB (E.), 

 America. 



