876 



SYSTEMATIC HISTORY OF THE INFUSOEIA. 



both recent and fossil. Europe, Asia, 

 Afi-ica, America. (vii. 46 ; ix. 154.) 

 Large ; length 1-216". Differs from a 

 Navicula only in having one margin of 

 the valves less convex than the other. 



C. heteropleura (E., K.). — Valves 

 broadly lanceolate, with unequally con- 

 vex sides, suddenly contracted into short, 

 broad, very obtuse, beak-like apices ; 

 striae distinct. KB. p. 19. = Plmiulana 

 heteropleura, EM. pi. 5. 2. f. 11. North 

 America. Large ; allied to C. JEhren- 

 hergii, but with more obtuse apices. 



C. cuspidata (K.). — Valves broadly 

 lanceolate, with unequally convex sides, 

 suddenly contracted into subacute, short, 

 rostrate apices ; strise delicate, 18 to 20 

 in 1-1200". KB. p. 79, t. 3. f. 40 ; SBD. i. 

 p. 18, pi. 2. f. 22. Europe. 1-576". 

 (^11. 45.) Differs from the preceding 

 species in its smaller size, more graceful 

 form, and narrow beaks. 



C. rostrata (Rab.). — Valves semilu- 

 nate, wdth dorsum strongly and venter 

 slightly convex ; ends produced into 

 short, subacute beaks ; striae dotted, con- 

 verging, 12 or 13 in 1-1200". Rab D. 

 p. 22, pi. 7. f. 5. Italy. SmaU. Very 

 nearly allied to C. cuspidata. 



C. porrecta (Rab.). — Valves turgid- 

 lanceolate, with unequal margins ; ends 

 produced into rather long, stout, obtuse 

 beaks ; striae stout, somewhat converg- 

 ing, 6 in 1-1200". Rab D. p. 22, pi. 10. 

 f. 10. Italy. Venter less turgid than 

 the dorsum. 



C. fortncata (Rab.). — Valves lunate, 

 with very fine convex dorsum, gibbous 

 venter, and produced, obtuse, rostrate 

 ends ; striae fine, smooth, 7 or 8 in 

 1-1200". Rab D. p. 22, pi. 10. f. 9. 

 Persia. 



C. amphicephala (Nag.). — Smooth ; 

 valves elliptic, with unequal sides and 

 produced capitate apices; front view 

 oblong with truncate ends. KSA. p. 890. 

 Switzerland. 



C. cequalis (S.). — Valves lanceolate, 

 nearly symmetrical, with shortly pro- 

 duced, slightly curved, obtuse extre- 

 mities : stride fine, 30 in -001". SBD. ii. 

 p. 84 ; ' Grev. in ANH. 2 ser. xv. pi. 9. 

 f. 4. Britain. A very distinct species, 

 which differs from Navicula only by the 

 slightly curved ends, Grev. 



O.pachycephala (Rab.). — Valves semi- 

 lunate, curved, with veiy convex dorsum 

 and gibbous venter, sti'ongly constricted 

 beneath the produced capitate apices: 

 striae granulate, somewhat converging, 

 7 or 8 in 1-1200". ^ Rab D. p. 22. = C. 

 eurycephala, Rab. t. 7. f. 10. Servia. 



C. epithemtoides (Rab.). — Valves arcu- 

 ate, with convex dorsum, concave venter, 

 and produced, obtuse, slightly recm-ved 

 ends ; striae stout, somewhat converg- 

 ing, 6 in 1-1200". RabD. p. 22.= a 

 costata, Rab. t. 7. f. 16. Salzburg. 

 Like an Epithemia, but having a central 

 nodule. 



C. Gregorii (Ralfs). — Valves arcuate, 

 with convex dorsum, straight venter, and 

 Slightly produced truncate apices ; striae 

 distinct. = C. truncata, Greg, in MJ. iii. 

 p. 38, pi. 4. f. 3. Scotland. Small. 



C turgida (Greg.). — Valves lunate, 

 with turgid, convex dorsum, nearly 

 straight venter, and produced, minute, 

 acute apices; striae very conspicuous, 

 about 24 in -001". Greg MJ. iv. p. 5, 

 pi. 1. f. 18. Scotland, America. 



C. Pisciculus (Greg.). — Valves lanceo- 

 late, with convex dorsmn, nearly straight 

 venter, and obtuse, subcapitate apices; 

 strijE about 30 in -001". Greg, in MJ. 

 iv. p. 6, pi. 1. f. 20. Britain. 



C excisa (K.). — Valves semilunate, 

 with slightly recm-ved, produced apices, 

 very convex dorsum, and a straight 

 venter, notched at its middle ; striae 16 

 in 1-1200". KB. p. 80, pi. 6. f. 17. 

 Europe. Minute. 



2 1 Apices neither rostrate nor capitate. 



C. affinis (K.). — Valves lanceolate, 

 with subacute, scarcely produced apices, 

 and the dorsal margin more convex than 

 the ventral ; striae faint, 19 in 1-1200". 

 IvB. p. 80, pi. 6. f. 15 ; SBD. i. p. 18, pi. 30, 

 f. 250. = Cocconema Fusidium, EM. many 

 figm'es. Europe, Asia, Australia, Africa, 

 America. Minute; terminal nodides 

 large. 1-1150" to 1-620". 



C. delicatula (K.). — Valves imequally 

 and narrowly lanceolate, smooth. KSA. 

 p. 59. France. Minute. 1-1200". 



C. ohtmiuscula (K.). — Valves lanceo- 

 late, with one margin rather less convex 

 than the other ; apices somewhat obtuse, 

 not produced; striae fine, 18 to 20 in 

 1-1200". KB. p. 79, pi. 3. f. 68. Europe. 

 1-600". Differs from a Na\-icida only by 

 its slightly imequal margins. 



C. Helvetica (K.). — Valves elongated, 

 somewhat arched, slender-lanceolate, 

 with slightly gibbous venter, and rather 

 obtuse apices ; striae fine, granulated, 13 

 or 14 in 1-1200". SD. i. p. 18, pi. 2. f. 24. 

 Europe, (xi v. 24-28.) Large. 1-264" 

 to 1-240". Front view oblong, trim- 

 cate. Akin to C. gastroides, but more 

 slender, K. 



C. maxima (Nag.). — Valves slender, 

 with attenuated, rather obtuse ends, and 



