OF THE SrRIEELLEiE. 



799 



we consider judiciously, adopted that suggestion. ^'The species included 

 under this genus may all be recognized by the characteristic bend or con- 

 tortion of their surfaces." — Sm. Cocconeis differs in its small size and cen- 

 tral nodule. 



* Disc circular, or tiearlyso, iciih a single 

 series of marginal costce, 



t Costae all radiant, forming a mai'ginal 

 circle. 



Campyxodiscus Horologiimi (Wil- 

 liamson). — Disc nearly flat, with a mar- 

 ginal circle of numerous (about 50) equal, 

 radiating costee, having a circle of close, 

 very short and flue strise at its inner, and 

 another at its outer edge, and enclosing 

 a large, central, orbicular, smooth space. 

 SBD. pi. 6. f 51. Marine. Scotland. 

 The costae are proportionally shorter in 

 this large species than in most others, 

 and occupy about one-third of the radius. 



C. limhatus (Breb.). — Disc with a mar- 

 ginal circle of short costae, continued by 

 an inner fainter circle of moniliform lines, 

 gradually lost in an indefinite, smooth 

 central space. BD. p. 12. f 1; GDC. p. 32, 

 pi. 3. f 55. Marine. France, Scotland. 

 " Distinguished from C. Horologium by 

 its finer costas and granulated disc," 

 Breb. " Gestae broad, transversely sul- 

 cate, so as to appear on close inspection 

 almost moniliform. Within this mar- 

 ginal band is another fainter band, which 

 looks almost like the reflection in a mir- 

 ror of the first, except that the bars are 

 more directly moniliform," Greg. This 

 species might be placed with almost equal 

 propriety in the section with double series 

 of costae. 



C. imperialis (Grev.). — Costae 3 in 

 •001", fonning a mag-nificent band, ac- 

 companied at base by short bifid seg- 

 ments ; central area broadly elliptical, 

 furnished Avith narrow, transverse, mo- 

 niliform striae, inteiTupted by a median 

 blank line. Gr TMS. ^^ii. p. 30, pi. 1. 

 f. 3. New Providence. In general ap- 

 pearance resembles C. limhatus, Breb. 

 but differs materially from that Diatom 

 on a closer examination. Grev. 



C. Kittonianus (Gr.). — Costae elon- 

 gated, transversely striated for two-thirds 

 of their length. Gr_ TMS. viii. p. 32, 

 pi. 1. f. 7. West Indies. Central space 

 famished with a median bar, as in C. no- 

 tatns, only less conspicuous, Grev. 



C. stellatus (Gr.). — Valve orbicidar, 

 with a narrow marginal band of close, 

 short costae, an inner circle of dotted 

 lines, and a central space marked with 

 irregular radiating lines. Gr MJ. vii. 



p. 157, pi. 7. f. 3. Califomian guano. 

 Costae 10 in -001". 



C. racliosus (F..). — Disc subcircular, 

 small, with smooth or obscurely punctate 

 centre, and border of about seventy 

 closelj'-set, radiating costae. KSA. t. 28. 

 f 12. Fossil. Vera Cruz. Upper Pe- 

 ruvian guano. We have noticed a Cam- 

 pylodiscus in Bolivian guano, and sup- 

 posed it to be this species. The costae 

 are numerous, radiating, and unequal, 

 enclosing a quadrilateral, obsoletely 

 punctate central space, divided by a 

 median hyaline line, and having at its 

 angles 3-4 converging costae. 



C. vulcanius (E.). — Disc large, sub- 

 orbicidar, flexuose, with about 42 mar- 

 ginal ravs, and smooth centre. KSA. 

 p. 33. Peru. 



C. hicruciatus (Greg.). — Disc circidar, 

 with a square median space occupied by 

 crossed striae, and prolonged to margin 

 by four pairs of tapering, transversely 

 striate processes in a crucial manner, each 

 inten-al with four strong radiant costae. 

 Greg MT. v. p. 78, pi. 1. f 42. Marine. 

 Glenshira, Scotland. A very peculiar 

 species, but difficult to describe. The 

 square centre is lattice-like, and itself 

 obscm-ely subdivided into smaller qua- 

 drate portions ; from it proceed to the 

 margin, in a crucial manner, foiu' pairs 

 of conical prolongations; the intervals 

 between the pairs are occupied by strong 

 rays, which, together with the striated 

 prolongations, are connected within the 

 margin in a scolloped manner. 



2 1 Disc more or less evidently divided 

 into lateral portions by a median line 

 or band ; costae imperfectly radiant. 



C. Hibernicus (E.). — Disc tortuous, 

 with numerous (30 to 40) continuous, 

 imperfectly-radiant costae, enclosing an 

 irregularly shaped, minutely punctated 

 central space. EM. pi. 15 a. f. 9. = C. cos- 

 tatiis, SBD. i. pi. 6. f.52. Aquatic. Britain. 

 (jY. 38.) The costae are loosely disposed 

 (4 in 1-1152"), slightly rough fi-om mi- 

 nute granides, and extend in length about 

 half the radius. Their radiant arrange- 

 ment is somewhat imperfect, from the 

 convergence of two or more at each end. 

 IVIi'. Norman has gathered this species 

 very pure near Hidl. 



C. Noricus (E.). — Disc suborbicidar, 



