A F0881L MARINE DIATOMACEOUS DEPOSIT. V 



processes, which are small, submarginal, and 4-9 in number. 

 Extreme margin striated. Diameter up to '0066" ; cellules seven 

 to eight in '001". Not very rare. — PL II, Figs. 8 and 9. 



A. Beeverice, Johnson (" Prich.," p. 844, PI. 6, Fig. 5). — Forms 

 with three or four processes are not unfrequent. Diameter "005". 

 A form with only two processes also occurs. 



A. ajigulatus, Grev. (" T. M. S.," Vol. xi, p. 71, PI. 5, Fig. 15; 

 u Schm. Atl.," PI. 34, Fig. 8). — Not unfrequent. Processes 8 or 

 9 ; the size varies considerably from *005" to •Oil" in diameter. 



A. margaritaceus, Ralfs. ("Prich.," p. 844; "Schm. Atl.," PI. 

 37). — A form with four processes, , 007 // in diameter, occurs ; a 

 very large variety (with processes up to 11), attaining a diameter of 

 •028", is not very rare in the heaviest density. 



A. amcenus, Grev., var. sparso-radiata, n. var. Gr. & St. (Grev. 

 in « T. M. S.," Vol. xii,p. 10, PI. 1, Fig. 3).— Differs from the type 

 by its larger size, and the greater distance between the radiating 

 lines of granules. Diameter up to *009". Lines of granules six in 

 •001". Smaller forms more closely resemble the type, while the 

 largest ones suggest A. oreganus. The processes vary up to 10 in 

 number ; and the disc is not convex. Not unfrequent. 



A. Sollittianus, Norm. var. nova Zealandica, n. var. Gr. & St. 

 (Norm, in " T. M. S.," Vol. ix, p. 7, PI. 2, Fig. 5).— In general 

 aspect resembles the type ; but is smaller, with only three processes, 

 and a well-defined, striated margin. The umbilicus is sometimes 

 wanting. The cellules are about 11 in "001", and the diameter 

 varies up to -0075". Not rare. (PL III, Fig. 10.) 



A. ?iotatus, n. sp., Gr. & St. — Valve small with indistinct 

 umbilical space, and four large opposite, almost circular, hyaline, 

 submarginal spaces about •001" diam. ; from the centre of each of 

 which projects a very short urn-shaped process. The valve is 

 slightly inflated towards the processes, leaving between the hyaline 

 spaces a slight depression ; the surface is covered with fine radia- 

 ting granules, which at the centre are irregularly arranged. The 

 furrows are narrow, but quite distinct ; the margin is well defined 

 by a clear zone. Diameter, *004". Rare. A very delicate form, 

 distinguished from other species in the genus by the large hyaline 

 spaces. (PL III, Fig. 11.) 



Glyphodiscus stellatus, Grev. (" T. M. S." Vol. x, p. 91, PL 9, 

 Fig. 5.) — Scarce. Similar to that occurring in the Californian 

 deposits ; up to -0035" in diameter. 



