91* BBIGHTWELL, ON DIATOMACEyE. 



spines arc occasionally detected in the margin j each segment 

 with one or two elevated processes ; unibilicate, with the sur- 

 faces of the valve, except the umbilicus, punctate. Diameter 

 •0(J1 to -077. Shell cleanings. 



19. Actinophcenia splendois, Shadbolt. — Valve with two 

 plates, one with very fine oblique markings, the other with 

 much coarser markings, arranged in a somewhat pinnate 

 manner. (PI. VI, fig. 15.) 



A common species, varying greatly in size and number of 

 segments. Brick fields, Caermarthen, Mr. Okeden. Very 

 fine. 



Syn. — Actinocyclus octodenarius, and numerous other species 

 of Ehrenberg : — Actinocyclus duodenarius, sedenarius, octode- 

 harius. Actinocyclus sedenarius, Roper ( f Micr. Journ./ vol. ii, 

 pi. VI, fig. 2). — Mr. Roper's figure is unsatisfactory, giving 

 only the fine markings. (Smith, ' Syn. Brit. Diat./ vol. ii, 

 Appendix, p. 86.) Professor Smith has published, with 

 doubts as to their distinctness, the three species named 

 above, which are certainly only varieties. It is unfortunate 

 that he should have transferred these names from the genus 

 Actinoptychus, in which they were placed by Ehr., to that of 

 Actinocyclus, creating thus the greatest confusion. Ehren- 

 bcrg's* Actinoptychus duodenarius, sedenarius, bioctodenurius, 

 Ave believe to be totally different from the form in question. 



20. Actinoptychus interpunctatus , n. sp. — Valves with an in- 

 definite number of double rays, running from the centre to 

 near the circumference, the rays composed of short broken 

 lines, the interstices between the pairs of rays filled up with 

 minute puncta, or dots. (PL VI, fig. 17.) 



Hub. West Indies ; Monterey ; New Zealand. 



Not an uncommon marine species, from various localities, 

 and allied to Eupodiscus Ralfsii and Eup. spar sits. 



The true species of this and the preceding genus Ave 

 believe to be few, while Ehrenberg, falling into the extra- 

 ordinary error of viewing every variety in the number of 

 rays or septa as a species, has made a fresh nomenclature 

 and a new description of nearly all the species necessary. 



21. Asterolampra Marylandica. — A variety with six seg- 

 ments, the normal number being eight. (PI. V, fig. 3.) 



22. Aulacodiscus sculpt us {Eupodiscus sculpt us), Smith. — 

 (PI. Y, fig. r., a front view.) 



Not often seen ; and not before figured in this aspect, to 

 our knowledge. 



