894 



SYSTEMATIC HISTORY OF THE INTUSOIIIA. 



bisson regards this form as distinct from j 

 N. Crabro, E. ; and it undoubtedly is 

 from the Trinidad Diatom figured by 

 Dr. Greville for that species. We con- 

 sider, however, that N. Pandura, Breb. 

 not only agrees in its smooth costae with 

 Ehrenberg's description and figure of N. \ 

 Crabro, but also better in shape than i 

 does Greville's N. Crabro, in which the ; 

 constricted portion is less elongated — a j 

 fact pointed out by Greville himself. i 



N. Crabro (E., K.). — Panduriform, \ 

 deeply constricted; lobes ovate or ob- 

 long, with subacute apices ; striae di- 

 stinct, obscurely moniliform, nitescent, 

 10 in -001". KA. p. 83 ? ; SBD. ii. p. 94 ; 

 MJ. V. pi. 3. f. '\l. = Pi?inularia Crabro, 

 ERBA. 1844, p. 85 ? ; Biploneis Crabro, 

 EM. pi. 19. f. 29 ? Fossil, yEgina; re- 

 cent, America, Em-ope. Although we defer 

 to the opinions of Brebisson, Smith, and 

 Greville, yet we think it highly probable 

 that the preceding species is the one 

 intended by Ehrenberg for D. Crabro. 



N. gemmata (Grev.). — Broad linear- 

 oblong, obtuse, with straight or slightly 

 concave sides ; striae moniliform, inter- 

 rupted, 10 in -001", wath a single row of 

 pimcta near the median line. Edin. 

 New Phil. Journ. n.s. x. pi. 4. f. 7. Cali- 

 fornian guano. Distinguished by its 

 distant striae, which form a linear mar- 

 ginal band. Its affinity is with N. Crabro 

 and its allies. 



N. tiodulosa (Breb., K.). — Minute, ob- 

 long, constricted at the middle ; ends 

 contracted into obtuse mammiform 

 beaks ; transverse striae not reaching the 

 median line. KB. p. 101, pi. 28. f. 71. = 

 Pinnularia Termes, EM. pi. 39. f. 100. 

 Recent, Cuba, Mexico, Africa; fossil, 

 Franzensbad. 



N. fiemina (E.). — Small, striated, 

 divided by a median constriction in both 

 views into two lenticular lobes; in lateral 

 view terminated by a median apiculus. 

 EB. 1840, p. 19. Mouth of the River 

 Elbe. 1-840" to 1-648". 



N. A^ns (E., K.). — Oblong, so much 

 constricted as to be nearly divided into 

 two semiorbicular lobes; striae slender, 

 granulate ; stricture smooth. KB. p. 100, 

 pi. 28. f. 76. =Pmmdaria Apis, EA. iii. 

 pi. 7. f. 18. Mexico, Africa. Distin- 

 guished by its smooth stricture and its 

 finely granulate striae (12 in 1-1200"). 



N. interrnpta (K.). — Sinuato-con- 

 stricted at the middle, with broadly ellip- 

 tic lobes and rounded ends ; striae inter- 

 rupted opposite the nodule. KB. p. 100, 

 pi. 29. f. 93. = Navicula, BAJ. 1842, 

 pi. 2. f. 18. Marine. America, Jutland. 



B. Valves divided into three or more pov' 

 tio)is by two or four constrictions, but 

 not constricted at the centre (Nodosae). 



N. Silicula (E.). — Smooth, linear 

 elongated, divided by two constrictions 

 into three nearly equal nodes ; apices 

 obtuse. EM. numerous figures. = N. 

 ventricosa, E. Apparently common, since 

 Ehrenberg gives upwards of fifty habi- 

 tats in Europe, Asia, Australia, Africa, 

 and America. This species might be 

 placed with almost equal propriety in 

 the following section. 



N. p)olyonca (Breb.). — Elongated, ba- 

 cillar, sublinear, divided by two con- 

 strictions into three nodes, the middle 

 one largest ; ends roundish-capitate ; 

 striae wanting or indistinct. KA. p. 85. 

 = Pinnularia undidata, MJ. ii. p. 97, pi. 

 4. f. 10. France, Britain. 



N. Hitchcockii (E.). — Smooth, linear- 

 oblong, each margin with three imdula- 

 tions; apices suddenly cuneate, sub- 

 acute. EM. pi. 5. 3. f. 11. America. 

 (VII. 62.) 



N. litnosa (K,). — Smooth or obscurely 

 striated, linear, with two constrictions 

 and three inflations, the middle one 

 largest ; ends cuneate, subacute. KB. 

 pi. 3. f. 50. German3^ 



N. nodosa (E.). — Linear, smooth or ob- 

 scurely striated, with three nearly equal 

 inflations; ends contracted into short ob- 

 tuse beaks.^ KB. p. 100, pi. 28. f. 82. Com- 

 mon, especially in small pools by the road- 

 side, (ix. 143.) j3, striae more evident. = 

 Pinnularia Legumen, EM. many figures. 

 1-430". Approaches N. Hitchcockii. 



N. trinodisl^.). — Valves with two con- 

 strictions, three nearly equal inflations, 

 roimded ends, and obscm-e striae. 



N. mesolepta (E.). — Smooth, elongated, 

 linear, with three inflations, the middle 

 one smallest; ends strongly contracted 

 into short obtuse beaks. EM. pi. 17. 

 2. f. 17. America, France. 1-420". 



N.wu'a//s(E.). — Minute ; linear, some- 

 what narrow in the middle, with tri- 

 crenate sides and obtuse apices. EB. 

 1853, p. 528 ; EM. pi. 35 b. a 2. f. 5. 

 Monte Rosa. Differs from iV. undosa in 

 its stouter apices : N. nodosa is larger and 

 more slender. Ehrenberg's figure shows 

 the valves very minute, with four con- 

 strictions and five nodules, including the 

 capitate ends, which nearly resemble the 

 others in size and form. 



N. Formica (E.). — Smooth, linear, 

 with four constrictions and five oblong 

 nodes. EM. pi. 4. 3, f. 8. Recent, United 

 States ; fossil, Finland. 



