OF THE N-iTICFLE^. 



897 



lanceolate, somewhat contracted towards 

 the rounded ends ; costas radiate at cen- 

 tre, interrupted bv a smooth ti;ansyerse 

 median fascia, 11 in -001", = Pinmdaria 

 diver gens, SD. i. p. 57, pi. 18. f. 177. 

 Britain. The costse near the central no- 

 dule are shorter and radiant ; the others 

 are divergent. 



N. Brebissonii (K.). — Linear -oblong-, 

 with obtuse ends ; costte fine, indistinct, 

 close, 30 in -001", not reaching- the me- 

 dian line, interrupted by a transverse 

 median fascia. KB. p. 93, pi. 3. f. 49. = 

 Pinnularia stauroneiformis, SD. i. p. 57, 

 pi. 19. f. 178. Europe. Front view 

 linear, with rounded angles. 



N. glohiceps (Greg.). — Minute, narrow 

 linear-oblong, constricted beneath the 

 globular ends; costse fine, distinct, not 

 reaching the median line, interrupted by 

 a transverse median blank band, 36 to 

 40 in -001" . = Pin ?mlana glohiceps, MJ. 

 iv. p. 10, pi. 1. f. 34. Scotland. Di- 

 stinguished by its capitate apices and 

 transverse cross-lihe median band, 



N. parva (E,). — linear, constricted 

 beneath the capitate ends ; costse 24 in 

 •001", interrupted at the middle by a 

 transverse, blank, cross-like band. = Siau- 

 roptera parva, EA. p. 135, pi. 3. 1. f. 19 j 

 Stauroneisparm, KB. p. 106, pi. 29. f. 23 ; 

 Pinnularia interrupta, SBD. i. p. 59, 

 pi. 19. f. 184. Em-ope, Asia, America. 

 Transverse band dilated outwards. 



N. Bohemica, EM. pi. 10. 1. f. 4. 

 Bohemia. Ehrenberg's figure is rhom- 

 boid, vidth obtuse apices, three median 

 lines, between which and the margins 

 are longitudinal series of dots, all inter- 

 rupted by a transverse median blank 

 space, but no distinct nodule ; front view 

 nan'ow-linear, with rounded ends. 



N. Claviculus (Greg.). — Narrow-linear, 

 with two constrictions ; central inflation 

 small, smooth; terminal ones oblong- 

 clavate, striated; strise parallel, nearly 

 reaching the median line, about 32 in 

 •001". GD. p. 6, pi. 1. f. 5. Scotland. 

 Nodule definite ; front view linear, with 

 roimded angles, broader than the lateral 

 view, the margins striated except at the 

 middle. 



E. Frustules in the lateral view having the 

 stricB on each side of the median line 

 divided into two series (a marginal and 

 a median) hy a longitudinal line, blank 

 space, or fascia. 



t Valves elliptic. 



N. Lyra (E.). — Elliptic or elliptic- 

 oblong, marked by two naiTow longi- 



tudinal blank spaces, which are con- 

 nected by the central nodule, in the form 

 of a Ip-e ; striae 22 to 24 in -001", often 

 indistinct, the middle ones longest. = 

 Navicula and Pinmdaria Lyra, E., GD. 

 p. 13, pi. 1. f. 13; N. Gregoriana, Grev, 

 MJ. V. p. 10, pi. 3. f. 7. Marine. Europe, 

 Asia, Africa, America. N. Lyra, var. recta, 

 Grev., large, oblong-lanceolate obtuse; 

 blank lines narrow, contracted at the no- 

 dule, otherwise parallel with the median 

 line ; striae 24 in -001" : Edin. New Phil. 

 Jour,, n.St, X. pi. 4. f. 3 : Califomian 

 guano : distinguished b}^ its large size 

 and straight blank lines. Either N, Lyra 

 is very variable, or more than one species 

 has been included under the name. The 

 valve is either rounded at the ends or 

 (more usually) has a short, produced, 

 cx)nical point. The blank spaces are 

 linear, inclined inwards at the nodule, 

 and the tips, which are attenuated, usu- 

 ally bent outwards, but are sometimes 

 straight or even incurved. 



_N. approximata (Grev,). — Oblong, 

 with produced, conic apices ; striae inter- 

 rupted, 17 in -001" ; outer band broad, not 

 dilated opposite the nodule ; blank lines 

 linear, nearly sti'aight. Grev, Edin, New 

 Phil. Jour., U.S., x. pi. 4. f. 10. Californian 

 guano. Allied to N. Lyra, but distin- 

 guished by the total absence of any con- 

 traction of the blank spaces opposite the 

 nodule. From N. Hennedyi it difters in 

 its linear, subparallel blank spaces, and 

 larger blank space round the nodule. 



N. irrorata (Grev.).~Broad, parallelo- 

 gramic or oblong, suddenly contracted 

 at the ends into mammiform apices ; 

 striae 15 in •OOl", fomiing a broad-linear 

 marginal band, and a narrow one of very 

 imequal breadth next the median line ; 

 blank spaces not reaching the ends. 

 Grev. /. c. f. 1. Californian guano. 



N. forcipata (Grev.). — Oval or oblong, 

 with rounded apices, and marked by two 

 narrow longitudinal blank spaces, which 

 diverge from the nodule in a cm^ved 

 manner and converge at the apices; 

 striae 35 in -001", the middle ones longest. 

 MJ. vii. pi. 6. f. 10, 11. Marine. Britain. 

 Distinguished from N. Lyra by its 

 smaller size, closer striae, and connivent 

 points of the blank spaces. 



N. mimmularia (Grev.). — Suborbi- 

 cular; striae moniliform, about 24 in 

 •001", interrupted by two narrow-linear 

 blank lines which contract opposite the 

 nodule, then cm^v^e outwards, converge, 

 and meet at the terminal nodides. Grey. 

 Edin. New Phil. Jom'., n.s., x. pi. 4. f. 6. 

 Californian guano. Valve small; striae 

 3 M 



