902 



SYSTEMATIC HISTOEY OF THE INFUSOEIA. 



ends into very short and broad, truncate 

 Leaks. Rab D. p. 40, pL 6. f. 70. Ger- 

 luany. Median line and nodide strongly 

 developed, liesembles Stauroneis platy- 

 stoina, but with a roimded, not trans- 

 verse median nodide. 



3t Valves linear. 



N. dicephala (E.). — Elongated linear, 

 constricted at the ends into capitate or 

 broadly conical beaks; striaj either ob- 

 ycure or distinct, 19 in 1-1200". = iVrti7- 

 culu and Pinmdaria dicephala, EM. many 

 ligures ; Pimmlaria biceps, Greg. M J. iv. 

 pi. 1. f. 28 ? Common. Em-ope, Asia, 

 Africa, America. 1-860" to 1-480". 



N. producta (S.). — Linear, abruptly 

 contracted at the ends into short, obtuse 

 beaks; strict faint, 42 to 48 in -001". 

 SD. i. p. 51, pi. 17. f. 144. = N. amphi- 

 n/uclms, SD. i. p. 51^ pi. 16. f. 142. Britain. 



N. birostris (E.). — Elongated narrow- 

 linear, suddenly contracted at the ends 

 into conical apices ; striee distinct, close, 

 parallel. = Pinmdaria birostris, EM. pi. 

 15 A. f. 24. Fossil, Lough Mourne de- 

 posit ; Sweden. This form seems scarcely 

 to differ from iV. dicephala, except in 

 having slenderer frustules. 



N. (fracillima (Greg.). — Slender, nar- 

 row-linear, constricted beneath the capi- 

 tate apices ; costie hue, 27 in -001", not 

 reaching the median line. = Pinmdaria 

 (/raciUima, MJ. iv. p. 9, pi. 1. f. 31 ; SD. 

 ii. p. 95 ; Pinmdaria tennis, MJ. ii. pi. 4. 

 f. 9 ? Britain. 



I^. linearis (Greg.). — Minute, narrow- 

 linear, constricted beneath the subcapi- 

 tate ends ; costse very fine, about 40 in 

 •001", parallel, reaching the median line. 

 = Pinmdaria linearis, MJ. iv. p. 8, pi. 1. 

 f. 29. Scotland. 



N. subcapifata (Greg.). — Minute, nar- 

 row-linear, constricted beneath the capi- 

 tate ends ; striiB subdistant, conspicuous, 

 short. = Pinmdaria subcajjitata, MJ. iv. 

 p. 9, pi. 1. f. 30. Scotland. 



N. Elyinensis (Greg.). — Minute, linear, 

 constricted beneath the subquadrate 

 capitate ends; strise fine, about 30 in 

 •001", slightly oblique, reaching the 

 median line. = Pinmdaria EJqinensis, MJ. 

 iv. p. 9, pi. 1. f. 33. Scotland. 



N. linqn'da (Perty). — Rather large, 

 striated, broadly linear-oblong, suddenly 

 contracted at the ends into short, broad, 

 obtuse beaks. Perty, Mic. Org. of Alps, 

 p. 204, pi. 17. f. 9. Alps. Front view 

 linear, with truncate ends; striae 10 to 

 11 in 1-1200". 



N. Pisciculus (E., K.). — Elongated, 

 slender, striated, narrow-linear, slightly 

 contracted at the ends into conic beaks ; 

 striae very delicate. KA. p. 75. = Pin- 

 nularia Pisciculus, EA. pi. 2. 1. f. 30. 

 Cayenne, India, Falaise. 



N. limbata (E.). — Small, linear, each 

 end suddenly contracted into a short, 

 broad, trimcate beak, and a wide border 

 appearing within. EA. p. 130, pi. 1. 2. 

 f. 16. Chili. 



N. lomjiceps (Greg.). — Minute, nar- 

 row-linear, with the ends contracted 

 into short, obtuse points; nodule inde- 

 tinite ; strite wanting or inconspicuous. 

 MJ. iv. p. 8, pi. 1. f. 27. Scotland. 



N. ajfinis (E.). — Small, linear-oblong, 

 with the ends suddenly contracted into 

 short, broad, obtuse beaks ; strias waiit- 

 iug or indistinct. EA. p. 129, pi. 2. 2. f.7; 

 SD, i. p,50, pi. 16. f. 143. Very common. 

 Ehrenberg gives upwards of seventv 

 habitats, (xii. 32.) 1-570" to 1-420". 

 Resembles N. dicephala. 



N. dubia (E.). — Small, linear-lanceo- 

 late, with the ends suddenly contracted 

 into conic beaks ; strise wanting or in- 

 distinct. EA. p. 130, pi. 2. 2. f. 8. Asia, 

 Australia, Africa, America. Akin to 

 N. ctjfinis. 



N. ambicjua (E,). — Small, oblong, 

 somewhat inflated, with the ends sud- 

 denly contracted into short, conic beaks ; 

 strine wanting or indistinct. EA. pi, 2, 2. 

 f. 9; EM, pi, 15 b, f. 15. America, Aus- 

 tralia, Lough Mourne deposit. Re- 

 sembles N. affinis and N. dicephala. 



N. rosfellata (K.). — Minute, striated, 

 linear-oblong, with elongated, rostrate, 

 acute apices. KB. p. 95, pi. 3. f. 65. 

 Wangeroog-e. 



N. columnar is (E.). — Large, elongated, 

 broadly linear, suddenly contracted into 

 short, very broad, rounded ends, and 

 marked by numerous longitudinal lines. 

 EM. pi. 14. f. 23. Berlin. 



N. ampliata, EM. pi. 17. 2. f. 7, & 

 pi. 15 A. f. 32. Finland, Siberia, Lough 

 Mourne deposit. Ehrenberg's figures re- 

 present this species as large, smooth, 

 iDroadly linear, suddenly contracted at 

 the ends into broad, romided, mammi- 

 form beaks. 



N. Vespa (R.). — Small, linear-oblong, 

 constricted beneath the capitate apices ; 

 nodules minute ; strife parallel, close, 

 nearly reaching the median line. =P<Vi- 

 mdaria Vespa, EM. pi. 33. 5. f. 9. Asia, 

 Africa, America. 



N. incurca (Greg.). — Small, linear, 

 with slightly smuated sides ; ends con- 

 tracted into short trimcate bealis ; stria) 



