890 



SYSTEMATIC HISTORY OF THE INFtlSOEIA. 



the lateral view lias an oblong inflated 

 centre, suddenly constricted al)oye into 

 a cone with rounded apex, and taper- 

 ing below into a slender base ; the front 

 view is large, broadly cimeate, with 

 striated lateral margins, rounded base, 

 and conspicuous puncta at upper end. 

 It differs from G. Glans in its larger size 

 and more elongated inflated centre. 



G. IlamUla, EM. pi. 37. 2. f. 10. Ore- 

 gon. Ehrenberg's flgure of the lateral 

 view resembles G. Oregonicinn, but is 

 stouter in proportion to its length, and 

 the basal end is shorter and more 

 truncate. 



G. giganteiim (E.). — Very large and 

 tiu'gid, distinctly striated, lanceolate, 

 the subacute apex rather more acute 

 than the base. EIIBA. 1852, p. 534. 

 Recent. California. It is more akin to 

 G. IfamiUa than to G. Herculeanmn, 

 but diflers in its larger size and slenderer 

 base. Centre inflated. 



G. Herculeamnn (E.). — Very large, 

 minutely striated, oblong, inflated at the 

 middle ; the ends attenuate and rounded, 

 the basal one slenderer. EM. pi. 35 a. 

 7. f. 12, 13. Lake Michigan, Niagara, 

 and Oregon. Stipes long, hyaline, dicho- 

 tomous ; length of frustule 1-216". Pro- 

 fessor Kiitzing miites this form to G. 

 geminatum ; but according to Ehrenberg's 

 figm-es, they are ver}^ di fferent. The upper 

 end is figured in this species as broadly 

 conical, not dilated into a head as in 

 G. geminatum. The front view is repre- 

 sented as more cimeate, and fm-nished 

 with conspicuous puncta at the upper 

 end. 



G. inti-icatiim (K.). — Inflated at the 

 middle, much produced at each end, 

 narrow, obtuse ; stipes rather rigid, mu- 

 cous, extremely interwoven, dichoto- 

 mous. KB. p. 87, pi. 9. f. 4. Germany. 

 Forms a firm slimy stratum on rocks. 

 1-420''. This species is described and 

 figured by Kiitzing and Eabenhorst as 

 slender, with inflated centre, whilst Smith 

 describes the British forms as lanceolate, 

 — a difference which renders their iden- 

 tity problematical. Front view narrow- 

 cuneate. 



G. longiceps, EM. pi. 7. 3b. f.9. Appa- 

 rently common, since Ehrenberg gives 

 thirty-eight habitats in Europe, Asia, 

 Australia, Africa, and America. We 

 have seen no description of this species ; 

 the figm'es represent it as narrow-cune- 

 ate in the front view, and the lateral 

 view striated, inflated at the centre, with 

 the ends elongated into beaks, the apex 

 obtuse, and the base truncate. 



G. veiitricosum (Greg.). — Much in- 

 flated at the centre, upper end conical, 

 lower slender, constricted above the 

 roundish base. Greg. MJ. p. 4, pi. 1. f. 40. 

 Scotland. -0013" to -0018". This form 

 much resembles G. Glans ; the base, how- 

 ever, is dilated and rounded — characters 

 wanting in the figures of that species. 



G. Cggnus (E.). — Narrow, T\'itli a lan- 

 ceolate inflated centre, and linear, elon- 

 gated, beak-like extremities. EM. pi. 5. 3. 

 f. 33. America, Asia. Obtuse at apex, 

 and truncate at base. Kiitzing thinks 

 this may be identical with his Splienella 

 rostellata. 



G. Vibrio (E.). — Elongated, inflated 

 at the middle, and gradually tapering 

 into long beak-like extremities : the 

 upper one subacute. EM. pi. 39. 3. f. 71. 

 Cayenne. SD. i. p. 81, pi. 38. f. 242. 

 (xn. 35.) "Akin to G. gracile, but 

 longer, more slender, and approaching 

 to Pinmdaria amphioxys^^ (E.). 



G. rostratiwi (Sm.). — Lateral view 

 ovate-elliptical, produced at the upper' 

 extremity into a linear obtuse rostrum, 

 slightly constricted below; striae 30 in 

 •001". SBD. ii. p. 99. Barlevlake, Co. 

 Cork. -0009" to -0012". Stipes distinct. 



G. ? Hehridense (Greg.). — Lateral view 

 elongated, narrow-lanceolate, -«dth in- 

 flated centre, acute equal apices, and 

 very fine striae. Greg. M J. ii. p. 99. pi. 4. 

 f. 19. Mull deposit. Professor Gregoiy 

 remarks that it seems to stand between 

 G. tenellum and G. Vibi'io, but that, only 

 its lateral \iew having been seen, its 

 genus is imcertain. 



6 * Frustules lanceolate in the lateral 

 view. 



G. dichotomum (K.). — Lateral view 

 naiTow-lanceolate, with slightly obtuse 

 apices, striated ; front view narrow- 

 linear, cuneate. SD. i. p. 79, pi. 28. 

 f. 240. = G. gracile, EM. numerous figures. 

 Common. 1-1150" to 1-860". Stipes 

 usually elongated and dichotomous, but 

 sometimes abbreviated and sub-simple. 

 The frustules somewhat resemble those 

 of G. olivaceiim, but are narrower ; their 

 puncta also are far less distinct. This 

 species appears generally diffused, since 

 Ehrenberg gives upwards of 100 habitats, 

 scattered over the world. 



G. lanceolatum (E.). — Lateral view 

 striated, lanceolate, with acute ends; 

 front view linear-cuneate, very gradu- 

 ally tapering at each end. KB. p. 87, 

 pi." 30. f. 59. America. Ehrenberg's 

 figures represent the lateral view broader 

 than in G. dichotomum. 



