OF THE SrRIEELLEJE. 



791 



but have interrupted costae ; the front 

 view, too, is very diflerent. (pnu. 6.) 



D. jfintiatum (E.). — Valve cruciform, 

 with angular lobes ; costae as in D. Har- 

 risonii.-=Staurosi7'a pinnata, EM, t. 5. 2. 

 f. 24; Odontidium Harrisonii, ^, Roper, 

 MJ. ii. p. 6, f. 6. Eiu'ope and America, 

 (\aii. 4.) 



D. speciosum (Brightwell). — Valve 

 subcruciform or rhomboidal ; angles 

 roimded, naked ; costse short, distinct, IG 

 on each side. = Odontidium speciosum, 

 BrightweU, JMS, vii. p. 180, pi. 9. f. 8. 



Doubtful species. 



D. Surirella = Fragilaria Surirella, 

 EM. pi. 39. 3. f.^ 54. Frustules large, 

 broadly linear, mth rounded ends and 

 marginal costae. 



D. Bcddjickii (Brightwell). — Valve 

 ovately rhomboidal ; costse about 20 on 

 each side, distinct, reaching nearly to 

 the ends, but leaving a linear open space 

 do^\^l the centre. In a clay or earthy 

 deposit from Baldjick, Mr. Nonnan.=: 

 Odontidium Bcddjickii, Brightwell^ /. c. 

 p. 180, pi. 9. f. 10. 



Genus STAUROSIEA (Eh.).—'' The form of this genus is that of qna- 

 di-angular Eragilarioe ; it is distinguished from the much larger forms of the 

 allied genus AmjDhitetras by the absence of (pseudo-) openings at the four 

 angles." — EEBA. 1843, p. 45. The above is the only notice of this genus we 

 have met with, the resemblance to Amphitetras is evidently very slight. 

 Erom Ehrenberg's figui'es, Staurosira seems to contain forms allied to Odon- 

 tidium and Eragilaria, which have the valve so inilated at the centre as to 

 appear 4-lobed, This character, however, is uncertain, since Professor Smith 

 shows that the same species has the valve sometimes inflated, and sometimes 

 constricted at the middle. 



SxAUROsrRA construens (E.). — Very 

 small, smooth ; valves spindle-shaped, 

 with the produced angles somewhat un- 

 equal. EM, several figures. Asia, 

 Africa, and America, (xv. 5.) 1-600". 

 Compare with Dimeregramma Tahel- 

 laria. 



S. amphilepta (E.). — Minute, smooth, 

 two of the produced angles larger and 

 more slender than the others. 



S. trigongyla, Asia; S. Epidendritim, 

 Chili ; S. Mea:icana, Mexico ; S. trica- 

 rinata, Mexico, — These species (Ehren- 

 berg's) are known to us only by name. 



G^nns EHAPHOJ^EIS (E.). — Frustules simple, free or shortly stipitate : 

 front view narrow linear ; valves much broader, with transverse dotted striae 

 and a median longitudinal line. Marine. Ehaphoneis diifers from Cocconeis 

 and Naviciila by the absence of a central nodule. The frustule has no alae ; 

 its striae are usually distinctly moniliform and divergent, and its median line 

 more conspicuous than in TryblioneUa. We have not thought it desirable to 

 separate Doryphora ; for it is doubtful whether Kiitzing's only species is even 

 specifically distinct from some forms still retained by lum in this genus. 



Rhaphoist.is Amphiceros (Ehr.). — 

 Valves lanceolate, about three times 

 as long as broad, with produced, styli- 

 form apices, and fine, dotted transverse 

 stri«. ERBA. 1844, p. 87 ; M. t. 18. f. 

 82. = Cocconeis Amphimros, E. 1840 ; 

 Doryphora Amphiceros, I^IB. p. 74 ; SBD. 

 i. pi. 24. f. 224. Marine. Europe and 

 America, (xiv. 21.) 1-576". Striae 18 

 to 20 in 1-1200". Ends suddenly con- 

 tracted and prolonged into a beak. 



R. Fusus (E.). — Valves slender, linear- 

 lanceolate, usually fom- times as long as 

 broad, with styliform apices, and 17 or 

 18 fine, transverse, granulated striae in 

 1-1200". ERBA. 1844, p. 87. Fossil. 

 Virginia. 1-720". Strongly akin in habit 

 to Fragilaria Amphiceros, but difters by 

 its median suture. 



R. Leptoceros (E.). — Valves long 

 lanceolate, quadi'angidar, rhomboid, three 

 times as long as broad, with long styli- 

 form apices and fine, granulated trans- 

 verse striae. ERBA. 1844, p. 87.=i2. 

 Oregonica, EM. pi. 18. f. 83. Fossil. 

 America. 1-720". Striae generally 18 

 in 1-1200". Has the habit of i2. Amphi- 

 ceros, but with much longer beaks. 



R. gemmifera (E.). — Large ; valves 

 elongated lanceolate, with long gradually 

 attenuated apices, usually three times 

 as long as broad ; striae strongly gi-anu- 

 lated, 10 in 1-1200". ERBA. 1844, p. 87. 

 Fossil. Mai7land. 1-300". 



R. iwetiosa (E.). — Large ; valves 

 broadly lanceolate, rhomboid, generally 

 twice as long as broad ; apices gradually 

 attenuated into beaks; striae stout, granu- 



