A Revision of the Genus Auliscus Ehrh., &c. By J. Rattray. 917 



6. Border narrow, hyaline or with faiut strife 7 



„ broader, more prominent, strife distinct 8 



7. Processes 4, subcircular, small. Markings i in O'Ol mm., 



subequal, without order ineonspicuus. 



„ 4, larger. Markings hexagonal, 4 in O'Ol mm.; 



rows fasciculate, subradial : a single distiact band 

 of smaller areolae around the processes, and of 

 larger unequal ones around the border . . . . radiatus. 



8. Processes 2, large. Markings 3 J to 4 in 0-01 mm., without 



order within the processes, in faint, oblique, curved, 

 decussating rows near border. Border with inner 



part hyaline, outer granular ocuJatus. 



„ 4. Markings subequal, 4; rows fasciculate, sub- 

 radial. Border with remote, coarse, and delicate 

 intervening striae hardmanianus, 



ROPERIA Grun. 



Roperia Grun., Van Heurck Syn. Diat. Belg. Explan., pi. cxviii. 



fig. 6. 



Circular or subcircular. Surface flat at centre, sloping gently 

 near border. Colour pale grey. Markings hexagonal, areolate, in 

 almost straight decussating rows at centre, subfasciculate towards the 

 border. A single small circular hyaline spot close to the border. — 

 Eujjodiseus pro parte Eoper, Quart. Journ. Mic. Sci., 1858, p. 19. 

 Actinocyclus pro parte Ealfs in Pritch. Inf., p. 835. 



R. tesselata Grun., Van Heurck Syn.- Diat. Belg., pi. cxviii. figs. 6, 7. 



Diam. from • 0575 to • 07 mm. Surface with slope around 

 border extending inwards for 1/8 to 1/10 of radius. Markings 6 in 

 • 01 mm., decreasing towards the border, the hyaline spot close to 

 the border from 0'0025 to O'OOB mm. broad. — Euioocliscus tesselatus 

 Eoper, Quart. Journ. Mic. Sci., 1858, p. 19, pi. iii. figs, la, Ih. 

 Actinocyclus tesselatus Ealfs in Pritch. In£, p. 835. 



This is not Goscinodiscus limbatus Ehrb. (Mikrog., pi. xx. fig. 29) 

 nor Goscinodiscus fimbriatus Ehi'b. (Mikrog., pi. xxii. fig. 2) as stated 

 by Eoper. 



Habitat : Caldy, Pembrokeshire (Eoper !) ; Ascidians, Hull (Gre- 

 gory ! Greville !) ; off Cape Einisterre, in 2360 fathoms (Greville !) ; 

 stomach of Fecten (Grove !) ; ' Gazelle ' Expedition (Weissflog !). 



FENESTRELLA Grev. 



Fenestrella Grev., Trans. Mic. Soc. Lond., 1863, p. 67. 



Frustules free, disciform. Surface slightly convex ; a small, semi- 

 circular, hyaline area, convex towards the border, on opposite sides of, 

 and at equal distances from, the central space, at about 3/5 of radius 

 from centre. Colour pale grey. Central space narrow, bent, but 

 elongate between the inner ends of the converging rows of areolae. 

 Markings hexagonal, areolate, minute around border, in evident rows 

 converging from central space to the semicircular hyaline areas, 

 elsewhere in fasciculate or radial, less conspicuous rows. 



