OF THE STJRIKELLE^. 



'93 



p. 36, pi. 30. f. 262. Fresh water. England. 

 •0021" to -0040". Strife 36 in -OOl". 



T. levidensis (S.). — Lateral view linear, 

 with subacute extremities ; costoe very 

 distinct, parallel, extending- to the cen- 

 tral line. SBD. ii. p. 89. Brackish 

 water. Cork City Park. 



T. punctata (S.). — Lateral view ellip- 

 tic, with acuminate ends and parallel, 

 transverse, moniliform strise ; canaliculi 

 obsolete. SBD. i. p. 36, pi. 30. f. 261. 

 Marine. Sussex. 



T. constricta (Greg.). — Lateral view 



panduriform, with apiculate ends and 

 numerous, delicate, diagonal, punctated 

 striae ; costa obsolete. Greg, in MJ. 

 iii. pi. 4. f. 13. Marine. Britain. " Its 

 form is that of Cymat(ypleura Soka, but 

 it is very much smaller.". — Greg. 



T. apiculata (Greg.). — Narrow, linear, 

 slightly constricted in the middle, with 

 apiculate extremities and about 45 fine 

 but distinct, transverse, dotted striae in 

 •001". Greg, in MJ. v. p. 79, pi. 1. f. 

 43. Scotland. -0015" to -0017". Keel 

 often strongly marked. 



Genus CYMATOPLEURA (S.).— Frustiiles free, in front view linear, with 

 undulated margins ; laterally broader, and marked \vath transverse bars. 

 Aquatic. This genus, instituted by Smith, is very distinct, and may be 

 recognized by the lateral surfaces projecting in the front view in an undu- 

 lated manner, the central portion being separated from the undulations by a 

 marginal row of dots. The lateral view is usually very much broader than 

 the front, which often renders it difficult to obtain a satisfactory sight of the 

 latter. The lateral surfaces, however, sufficiently identify the genus, as the 

 broad, transverse, shade-like bands or bars which correspond with the undu- 

 lations are characteristic. The striae are generally obscure or obsolete, and 

 the median longitudinal line is less evident than in Surii'eUa ; the margin 

 is usually furnished with conspicuous gland-like dots. " The undulations of 

 the valves separate Cymatopleui-a from TryblioneUa and Surirella ; the absence 

 of alse and canaliculi are fiu'ther characters which leave no room for hesita- 

 tion as to its distinctness." (Smith.) 



Cymatopleuba Solea (Breb., S.). — 

 Frustule elongate; laterally panduri- 

 form, with more or less attenuated ends, 

 sometimes apiculated ; striae delicate, 8 

 in 1-1200". SBD.i. p. 36, f. 78. = Surirella 

 Solea, Breb. in KSA. p. 34; S. Librile, 

 E. ; Sphinctocystis librilis, Hass BA. 

 p. 102, 3. Yar. j3, ends apiculated, = C. 

 apiculata, S. I. c. p. 37, f. 79. Common, 

 Asia, Africa, America, Europe, (ix. 155 ; 

 XVI. 9.) Frustules, in both \dews, many 

 times as long as broad ; undulations six. 

 The ends, in the lateral \dew are always 

 attenuated ; but theu' apices vary, and are 

 sometimes obtuse, sometimes apiculate ; 

 and therefore we concm- with M. de Bre- 

 bisson in uniting C. apiculata, Smith, 

 with this species. 



C. heterocyma (Nageli). — Lateral 

 view panduriform, with 16 marginal striae 

 in 1-1200" ; front view broadly linear, 

 twice undulately twisted, with six mar- 

 ginal {olds. = Surirella heterocyma, KSA. 

 p. 889. Switzerland. 1-240". 



C. elliptica (Breb., S.). — Lateral view 

 elliptic, with three to five transverse bars ; 

 ends, in general, slightly attenuated. 

 SBD. p. 37, pi. 10. f. 80. = SurireUa oo- 

 phcena, E. (according to Kiitzing) ; S. 

 undulata, EM. ; S. undata, EM, ; S. pli- 



cata, EM. pi. 15 a. f. 50, 51 ? ; S. 

 Kiitzim/ii, Perty, Diat. p. 201, t. 17. f. 2. 

 Aquatic. Asia, Africa, America, Europe, 

 (ix. 149; x\^. 7, 8.) Professor Kiitzmg 

 describes the frustules as ovate ; but we 

 have always found them elliptic. Un- 

 dulations three to five; lateral surfaces 

 obscurely striated and furnished with 

 marginal gland-like dots. We have re- 

 ferred the Surirella plicata, E., to this 

 species, because of its habitat, although 

 its figure in the ^Microgeologie' agrees 

 better with that of C. Hibernica. 



C. Hihernica (S.). — Lateral view 

 broadly elliptic, ^dth produced ends ; 

 striae obscm^e. SBD. i. p. 37, pi. 10. f. 

 81. Ireland, France. Undulations about 

 three ; length 1-370" to 1-220" ; breadth 

 two-thirds the length. 



C. Regula (E.). — Lateral view linear, 

 with cimeate ends and six transverse bars. 

 = Surirella Regula, KB. t. 28. f. 30. ; C. 

 parallela, Smith, BD. pi. 30. f. 263. 

 Mexico, France, England. Habit and 

 size of C. Solea, but not panduriform ; 

 pinnules 10 in 1-1200", nearly obsolete. 



C. Ovum (Nageli). — Lateral view 

 broadly oval, wdtli 8 marginal striae in 

 1-1200" ; front view broadly linear, 

 straight; margin Avith five marginal 



