OF THE CYMBELLE.E. 



8^ 



inflated venter ; striae 16 in 1-1200." 

 KSA. p. 890. Switzerland. 1-180" to 

 1-120". 



C. gastroides (K.). — Valves lunate, 

 with obtuse apices ; venter sliglitly con- 

 cave, with gibbous centre ; striae granu- 

 lated, 11 or 12 in 1-1200". KB. p. 79, 

 pi. 6. f. 4 6. Eui'ope. (xiY. 18-20.) 

 Large. 



C. truncata (Rab.). — Valves as in C. 

 gastroides, but with broadly truncate 

 apices. Rab D. p. 21 ; C. fulva, t. 7. f. 3. 

 = C. gastroides, KB. p. 79, pi. 6. f. 4 a. 

 Eiu'ope. 



C. leptoceras (E., K,). — Valves slender, 

 arcuate, with gibbous venter and attenu- 

 ate apices ; striae veiy fine, 17 in 1-1200". 

 KIB. p. 79, pi. 6. f. 14. = Cocconema lep- 

 toceras, EA and M. many figures. Eu- 

 rope, Asia, Australia, Africa, and Ame- 

 rica. Minute ; front view elliptic-oblong, 

 with rounded ends. 



C. macidata (K.). — Valves semiorbicu- 

 lar, with very convex dorsimi and straight 

 or gibbous venter ; striae very fine, 12 to 

 13 in 1-1200". KB. p. 79, pi. 6. f. 2. = 

 C. Lumda, Rab D. p. 23. = Cocconema 

 Lunula, EA and M. many figures. Com- 

 mon. Europe, Asia, Africa, America. 

 Minute ; front view elliptic, with trun- 

 cate ends. 



C. ohtusa (Greg.). — Valves semi-oval, 

 with very obtuse apices, convex dorsum, 

 and nearly straight venter; striae very 

 fine, inconspicuous, about 36 in -001". 

 Greg MJ. iv. p. 5, pi. 1. f. 19. Scotland. 

 Minute. 



C. ventricosa (Ag.). — Valves semilu- 

 nate, with very convex dorsum, straight 

 venter, and large, distinct terminal 

 nodules ; striae inconspicuous, 30 in 

 •001". Ag CD. p. 9; KB. p. 80, pi. 6. 

 f. 16; SBD. ii. p. 84. Em-ope. Minute. 



1-1000". Front view oblong, with trun- 

 cate ends. 



C. inicrostoma (Rab.). — Valves lunately 

 curved, with broadly obtuse ends ; dorsum 

 convex, depressed at the centre ; venter 

 concave ; nodules verv minute ; striae 

 smooth, 7 or 8 in 1-1200". Rab 1). p. 22, 

 t. 10. f. 3. Persia. 



C. Scotica (S.). — Valves slender, semi- 

 lanceolate, "wath straight ventral mai'gin 

 and acute apices; striae 42 in -001". 

 SD. i. p. 18, pi. 2. f. 25. Britain. 



C. gracilis (E., K.). — Valves slender, 

 semilanceolate, with straight or slightly 

 concave ventral margin and subacute 

 apices ; striae very fine or obsolete, 17 in 

 1-1200". KB. p. 79, pi. 6. f. 9.= Cocco- 

 nema gracile, EM. several figures. Eu- 

 rope, Asia, Africa, America. Lough 

 Mourne deposit. Small. 1-840" to 

 1-600". 



C. lunata (S.). — Valves narrow, lunate, 

 with slightly concave venter, and rather 

 obtuse apices ; striae distinct, 24 in 

 •001". SBD. ii. p. 84. Grev. in ANH. 

 2nd ser. xv. pi. 9. f. 5. Scotland. Di- 

 stinguished from C. Helvetica by its 

 smaller size and concave venter, and 

 from C. Scotica by its coarser striae and 

 obtuse ends, Grev. 



C. eurvata (Rab.). — Valves smooth, 

 lunate, with convex dorsimi, slightly con- 

 cave venter, and obtuse ends. Rab D. 

 p. 23, t. 7. f. 14. 6. Italy. 



C. ? Diance, E. = Cocconema Diance, 

 EM. pi. 15 A. f. 100 a. Lough Mom-ne 

 deposit. Small. Valves lunate, with 

 convex dorsum, concave venter, and ob- 

 tuse apices. 



C. ? Navicida = Cocconema Namcula, 

 EM. pi. 17. 2. f. 35. Finland. —Valve 

 lanceolate, with the dorsum rather more 

 convex than the venter. 



Genus COCCONEMA (Ehr.). — Frustules cymbiform, stipitate ; lateral 

 surfaces lunate, striated, and divided unequally by a longitudinal line with 

 median and terminal nodules. The frustules are similar in form to those of 

 CymbeUa, and when detached, their proper genus is often doubtful ; the lower 

 margin, however, is less frequently convex than it is in Cymbella. 



Cocconema lanceolatum (E.). — Front 

 view lanceolate, truncate ; valves elon- 

 gated, arcuate, or semilanceolate, centime 

 of venter gibbous ; striae moniliform, 21 

 in -001". EI. t. 19. f 6 ; SBD. i. p. 75, 

 pi. 23. f. 219. Europe, Asia, Australia, 

 Africa, America, (x. 194, 195.) Length 

 1-210" to 1-120". Venti-al margin of 

 frustide nearly straight, with slightly 

 gibbous centre; stipes dichotomous, 

 articulated. 



C. aspei'um (E.). — Habit and size of 

 C. lanceolatum, but with striae denticu- 

 late or interrupted by puncta. EM. 

 many figures. Australia, Asia, Ame- 

 rica ; fossil, France. 1-288". We fear 

 this form is scarcely distinct from C. 

 lanceolatum. 



C. fossile, EM. t. 19. f. 57. Greece. 

 Ehrenberg's figm-e represents a smaller 

 species than C. asperum, with straight 

 ventral margin, nearly marginal longi- 



