OF THE KAYICULE.E. 



903 



wanting or inconspicuous. MJ. iv. p. 8, 

 pi. 1. f.'2G. Scotland. 



N. apiculata (Breb.). — Striated, linear, 

 suddenly attenuated at eacli end into a 

 short apicuhis ; front \-iew broad, qua- 

 drate, with striated lateral margins ; 

 stride strong, 14 in -001", nearly reaching 

 the median line. Breb DC. p. 16, pi. 1. 

 f. 20. = Pifmulana rosteUata, GDC. p. 10, 

 pi. 1. f. 20. Marine. Europe. Striae 

 somewhat radiant. The frustules are 

 much compressed, and very similar in 

 the front view to those of N. retusa. 



4 1 Valves subquadrate or elliptical, with 



conical terminal points. 



N. lacustris (Greg.). — Small, oblong 

 or subquadrate, with acute or shortly 

 rostrate apices ; striae fine, distinct, 

 slightly oblique, nearly reaching the 

 median line, 28 or 30 in -001". MJ. iv. 

 p. 6, pi. 1. f. 2.3._ Scotland. The only 

 species ^^-itli which this could be con- 

 founded is N.Jirma', but the latter is 

 longer and larger, of a brown colour, 

 with finer, less conspicuous, and parallel 

 striae. 



N. humerosa (Breb.). — Siriated, sub- 

 quadrate ; ends trimcate, with a minute, 

 conic central point; stride fine, monili- 

 form, 24 in -001", radiant, reaching 

 nearly to the median line, shorter oppo- 

 site the roundish umbilical space. SD. 

 ii. p. 94. = N. quadrata, Greg. TM. iv. 

 p. 41, pi. 5. f. 5. Marine. Em^ope. Ac- 

 cording to Dr. Donkin, the dry valve, 

 under a low power, is hyaline and 

 colomiess. 



'^ . (/ramdata (Breb.). — Striated, rather 

 large, elliptic or subquadi-ate ; ends with 

 a conic central point ; striae conspi- 

 cuously monilifomi, 16 in -001", radiant, 

 reaching nearlv to the median line. 

 Donkin, TM. yi. pi. 3. f. 19. Marine. 

 Em-ope. Distinguished from N. hume- 

 rosa by its more distant and coarsely 

 granulated striae. " Dry valve of a dull 

 bluish colour, inclining to pm-ple " 

 (Donkin). 



N. compacia (Grev.). — Small, sub- 

 quadrate, with slightly concave sides, 

 rounded shoulders, and the median line 

 prolonged into conic points ; striae faint, 



42 in -001", reaching nearly to the me- 

 dian line. Greg. MJ. v. p. 11, pi. 3. f. 8. 

 Marine. Not ujicommon. The striae are 

 nearly parallel. A species well marked 

 by its quadrate shape. 



N. hdissima (Greg.). — Broadly elliptic, 

 with slightly produced mammiform 

 apices ; striae distinct, finely monilifomi, 



radiant, nearly reachhig the median line, 

 shorter, and leaving an orbicular hyaline 

 space round the central nodide, TM. iv. 

 p. 40, pi. 5. f. 4. Marine. Britain, 

 (vii. 70.) Distinguished from N. (jm- 

 nidata by its strav\" or light-brown colour 

 in balsam, and less conspicuous gianules. 



N. Barclayana (Greg.). — Elliptic- 

 oblong, with minute, conic apices ; striae 

 about 38 in -001", finely monilifomi, 

 short, forming a naiTow marginal band, 

 and enclosing a large, lanceolate smooth 

 median space. GDC. p. 8, pi. 1. f. 9. 

 Marine. Britain. The marginal striated 

 band is of nearly uniform breadth, ex- 

 cept near the base, where it becomes 

 naiTower. 



N. marma(^2i!d^. — Oval, with slightly 

 produced conic apices, and 33 distinct, 

 moniliform, radiant stiiie in -001", which 

 reach the median line. = N. punctidata, 

 SD. p. 52, pi. 16. f. 151. Marine. Eng- 

 land. 



Is", producta (Ralfs). — Oblong-elliptic, 

 much constricted at each end, as if ob- 

 tusely mucronate j surface elegantly 

 marked by decussating punctated lines ; 

 puncta in quincunx. = iV". decussafa, EB. 

 1843, p. 256. Habit of N. Amphkhcena. 



G. Vcdves lanceolate or rhomboid. 



N. rhomhoides (E.). — Rhomboid-lan- 

 ceolate, with subacute apices and 85, 

 verv faint, parallel stride in -001". EA. 

 pi. 3. 1. f. 15 ; SBD. i. p. 46, pi. 16. 

 f. 129. Mexico, Em'ope, Australia. 



N. rhomhica (Greg.). — Rhomboid- 

 lanceolate, vnXh. A'ery tine but distinct 

 striae, 45 in -001", reaching the median 

 line. MJ. iii. p. 40, pi. 3. f. 16 ; TM. iv. 

 p. 38, pi. 5. f. 1. Marine. Scotland, 

 (vn. 71.) According to Professor Gre- 

 gory, N. rhomhica is distinguished fi*om 

 N. rhomhoides by the difterent appear- 

 ance of its median line and central 

 nodide, as well as by its distinct striae. 



N. rliomhea (E.). — Broadly rhomboid- 

 lanceolate, with acute apices, and delicate 

 longitudinal lines on each side; trans- 

 verse striae wanting or indistinct. EA. 

 p. 131, pi. 3. 7. f. 27. Mexico. 1-480" 

 to 1-360". 



N. Bemeraroi (E.). — Smooth, rhom- 

 boid, tumid, strongly tapering into acute, 

 subrostrate apices. EB. 1845, p. 79. 

 Demerara. 1-576". ^' Distinguished from 

 N. rhomhea only by its subrostrate ends " 

 (Rabenhorst). 



N. decussata (E., K.). — Rhomboid- 

 lanceolate, A\T.th subacute apices, an ob- 

 solete umbilical space, and very fine, 



