OF THE STRIATELLE.E. 



805 



series of striae in the front view are also 

 more conspicuous. Leng-tli of frustule 

 1-570" to 1-200". 



E. Aclnaticum (K.). — Frustules with 

 four series of septa (two marginal and 

 two median, the latter shortest at one 

 lateral margin, and gradually longer as 

 they approach the other). SBD. ii. p. 35. 

 pi. 38. f. 305. Common, especially from 

 deep water. On Alg?e, which are sold 

 as " Corsican moss." (xiii. 27.) 1-480" 

 to 1-168". Easily distinguished by the 

 median series of septa, which, more con- 

 spicuous than the marginal ones, are 

 usually more or less curved or oblique, 

 and do not coincide with the ribs, but 

 cross the series of striae ; they also gra- 

 dually increase in length from one lateral 

 margin to the other, leaving a fimnel- 



shaped median space. 



li. Crozieri (E.). — Lateral valves 

 turgid ; apices obtuse, shortly attenu- 

 ated ; the perforated dissepiments (or 

 spurious joints) striated, varying in 

 number. = Striatella Crozieri, 'ERBA. 

 1853, p. 529. Assistance Bav. Stria) 

 18 in 1-1152". (iv. 43.) 



Species knoivn to tis only by name. 



R. mirificum (8.). — ^'A magnificent 

 species, with filaments occasionally reach- 

 ing -0086" in Avidth, and with alternate 

 and cribrose septa. Septa Avith several 

 (3 to 12) irregular perforations." SBD. 

 ii. p. 35. Mauritius and Ceylon. Arnott, 

 JMS. vi. p. 92 ; BrightAv. JMS. ^-ii. pi. 9. 

 f. 11. (Till. 12.) 



GeniLs STYLOBIBLIUM (E.).— Erastules cyHndrical, multivalved, not 

 concatenated, valves in a simple straight series, like the leaves of a closed 

 book, with a large median canal, entire (not perforated) at the ends ; sculp- 

 tured ; tube smooth. Fossil. Stylobiblinm approaches nearest to Biblarium 

 and Tetracyclus ; but the frustules in the lateral view are orbicular — a cha- 

 racter not met with in the other genera of this family. The species are 

 fossil, and occur only in a fragmentary state. 



Stylobiblium Clypeus (E.). — Lateral | blank band. EM. pi. 33. 12. f. 30. 



view with from 15 to 20 short, radiant 

 marginal lines, and 3 or 4 pervious, trans- 

 verse median ones, frustules in the front 

 view \x\ih about 34 laminse or annuli. 

 EM. pi. 33. 12. f. 28, 2^. = Biblarium 

 Clypeus, E. Oregon and Siberia. Dia- 

 meter 1-792". (iv. 45.) 



S. ilii'isum (E.). — Disc large, its centre 

 vAWx about 10 transverse parallel lines, 

 not reaching the margin, and separated 

 into two series by a linear longitudinal 



Oregon. Diameter 1-600". 



S. eccentricum (E.). — Disc with 5 to 7 

 eccentric, pervious, curved lines. EM. 

 pl.^33. 12. f. 31. Oregon. Diameter 

 1-760". A fragment of a cylinder con- 

 tained 9 annuli. The costae in Ehren- 

 berg's figure resemble those of Tetra- 

 cyclus, the median one straight, and 

 those above . and below cm-ved towards 

 the margin in opposite directions to each 

 other. 



Genus BIBLARIUM (E.). — Frustules compressed, lamelliform, with in- 

 ternal septa ; lateral view with transverse uninterrupted costae, but T\ithout 

 median inflation. Fossil. All the species are fossil, and, although described 

 by Ehrenberg as simple, were probably filamentous in a recent state. The 

 forms with inflated centre we concui^ with Professor Smith in removing to 

 Tetracyclus, and indeed only retain the genus because we are unable to 

 ascertain at present the proper situation of the other species noticed here. 



Biblarium compressum (E.). — Lateral 

 view eUiptic-oblong, with obtuse ends 

 and lax, parallel transverse costae. EM. 

 pi. 33. 12. f. 1. Oregon. 1-648". 

 Costae 5 to 7 in 1-1152". Septa 28 in 

 each frustide. 



B. elhpticum (E.). — Lateral view ellip- 

 tic, with broadly romided ends, and 5 to 

 8 parallel transverse striae in 1-1152". 

 EM. t. 33. 12. f. 2. Siberia and Oregon. 

 1-1080". Differs from B. compressum 



only in its more elliptic lateral valves. 



B. Lamina (E.). — Lateral valves 

 broadly linear, with rounded ends, 

 slightly constricted middle, and 7 to 8 

 parallel transverse striae in 1-1152". 

 EM. pi. 33. 12. f. 4.. Oregon. Ehren- 

 berg's figure shows little or no constric- 

 tion. 



B. linear e (E.). — Lateral valves nar- 

 rowly linear, with rounded or subacute 

 ends, and 4 to 8 parallel transverse striie 



