OF THE STllTATELLEJE. 



809 



that some of the allied species are not 

 really distinct from it. Professor Smith 

 informs us that, in this species, JNIr. West 

 finds the dots disposed in quincunx, and 

 the lines consequently oblique, (iv. 48.) 

 G. anguina (K, ). — Large, smooth ; 

 septa serpentine, with the interior end 

 hooked inwards. KB. t. 17. f. 25. At- 

 lantic and Antarctic Oceans. 1-650" to 

 1-360". We see not how this differs 

 from G. serpentina, as we believe that no 

 species in this genus is really smooth. 



2* Latei'al view with four constrictions. 

 G. undulata (E.). — Lateral view linear, 

 with four constrictions and rounded 

 ends ; septa in ft'ont view undulated. 



KB. t. 29. f. 68. Fossil, Greece ; recent, 

 America. 1-860". 



3 * Lateral view lunate. 



Gc. arcuata, EM. pi. 35 a. 23. f. 11, 12. 

 Assistance Bay. The figures represent 

 the front ^dew with undulated septa, 

 and the lateral one lunate, with trans- 

 verse lines and a central canal. 



G. curvata, EM. pi. 35 a. 22. f. 13. 

 Antarctic Ocean. The figure shows the 

 lateral view, like that of G. arcuata 5 but 

 its central canal is smaller, and there are 

 no transverse lines. 



G. subtilissima. — StrisD fine. A good 

 test for high powers. 



Genus GEPHYRIA (Arnott). — Frustules attached; front view with sub- 

 lamellate, finely striated connecting zone, destitute of septa ; valves arcuate, 

 dissimilar, with transverse costae internipted by a longitudinal Une. Marine. 

 We place Gephyria with the Striatelleai because of its resemblance to 

 Eupleuria; but the absence of septa renders its proper position somewhat 

 doubtful. The lower valve dififers from the upper one in having a smooth 

 circular space at each end. The strongly arched valves and absence of septa 

 distingiiish it from Eupleuria. It differs from Achnanthes by having no 

 central nodule. 



Gephybia incurvata (Ar.). — Costse of 

 valve about 7 in -001"; connecting zone 

 with stout longitudinal costae. Ai' M J. 

 viii. p. 20. = Eujileuria incurvata, Ar MJ. 

 vi. p. 90 ; Achnanthes costata, Johnstone, 

 M J. viii. p. 20, pi. 1. f. 14. South African 



and Patagonian guano. 



G. media (Ar.). — Valves obtuse, with 

 11 costse in -001". Ar MJ. viii. p. 20. 

 Achnanthes angustata, Johnstone, MJ. 

 viii. p. 20, pi. 1. f. 13. Califomian guano. (l9 , i,j 



G. Telfairiee (Ai\). — Valves ^^dth ^ 



acute cuneate ends, and 15 costas in 

 •001". ArMJ. \iii. p. 20. Mauritius. 



Genus EUPLEURIA (Arnott). — Frustules united into short, attached 

 filaments ; front "^iew annulate, indefinite, with short septa and beaded 

 margins ; valves dissimilar, costate ; costae interrupted by a longitudinal line, 

 those of lower valve fewer and central. Marine. Euplemia differs from 

 Rhabdonema by its dissimilar valves, the transverse costse of the lower one 

 being confined to the middle — a character conspicuous even in the front view, 

 since the ends of the costae are there seen as marginal bead-like dots. The 

 valves have some resemblance to those of Achnanthes, but have no central 

 nodule or stauros. 



Eupleuria pulchella (Ar.). — Front ; oblong. In the lower valve the costae 

 view ^^atll stout longitudinal costae con- | and longitudinal line are present only at 

 nected by transverse bars, very short | the middle portion, and leave a large 

 septa, and punctated lateral margins, hyaline blank space at each end. Striae 

 Ar TMS. vi. p. 89. New Zealand and j between the costae, and oblique. / KZTT - J^J 

 Australia. The frustules, in the fi-ont | E. oceUata (Ar.). — Front view with 

 view, have the cellulate structure of j longitudinal lines, fine transverse striae, 

 Rhabdonema ; but the septa are so abbre- j and costate lateral margins ; costae of 

 viated as to seem mere marginal dots, 1 ventral margin longer, confined to the 

 and the puncta on the ventral margin middle, and divergent. Ar TMS. vi. p. 9. 

 are confined to the middle. Annuli close, | New Zealand. In E. oceUata the frustides 

 numerous ; valves usually turgid at the are more hyaline than in E. pidchelluy 

 middle and rapidly tapering to the obtuse and the longitudinal costae less conspi- 

 apices (subovate), but sometimes linear- ciious, and not connected bv transverse 



