BRIGHT-WELL, ON DIATOMACE.E. 95 



23. Aulacodiscus radiatus, Bailey. — This is the true 

 Eupodiscus radiatus of the late Professor Bailey, as ascer- 

 tained by authentic specimens. (See Mr. Roper's remarks in 

 1 Micro. Journ./ vol. xix, pp. 19 and 262.) (PL V, fig. 10a, 

 side view ; b, diagram of front view.) 



24. Aulacodiscus Icevis. — A variety with eight, instead of four 

 processes. Allied to Scaber, but differs in the surface, being 

 perfectly smooth. (PI. VI, fig. 13.) 



25. Hyalodiscus cervinus, n. sp. — Valve, with exceedingly 

 minute puncta, or dots, scattered over the whole surface ; 

 centre, convex ; valves, fawn coloured. Diameter, '054 to 

 •085. (PL V, fig. 9.) Arctic regions, Dr. Sutherland. 

 Shell cleanings, "West Indies. Not uncommon. 



The peculiar lines mentioned by Bailey in his description 

 of H. sub tills, as characteristic of that species, cannot be 

 detected in this, which, in other respects, agrees with it. Mr. 

 T. West says, with the greatest care and best sight, he cannot 

 detect these lines. 



26. Craspedodiscus pyxidicula, Ehr. — Diameter of the 

 valve, *049; of the inner punctate portion, -021. (PL V, 

 fig. 4.) Guano, South America. 



We take this to be the species referred to. The central 

 third part of the valve is slightly punctate, the puncta 

 diminishing till they almost disappear in the centre. The 

 residue of the valve with regular hexagonal reticulations. 



27. Craspedodiscus marginatum, n. sp. — Valve, with a broad 

 impunctate margin, having about twenty rays, terminating 

 outwardly in small semicircles ; residue of the valve 

 minutely punctate. Diameter, '037. (PL V, fig. 7.) Bar- 

 badoes earth. 



28. Craspedodiscus semiplanus, n. sp. — Margin very broad, 

 with faint radii and puncta. One-half of central part of the 

 valve smooth, the remainder with four or five radii. Dia- 

 meter, -024 to -035. (PL VI, fig. 12.) Barbadoes earth. 



The margin is sometimes found impunctate. 



29. Craspedodiscus coronatus, n. sp. — Centre of the valve a 

 small circle, enclosed by a rim of large square puncta, and 

 having within smaller puncta, diminishing in size towards the 

 central point. Outer portion of the valve minutely punctate. 

 Diameter, -022 to -068. (PL V, fig. 6.) Barbadoes earth. 



