A Revision of the Genus Auliscus Elirh., do. By J. Rattray. 919 



broad. Markings minute, punctate, in faint lines passing obliquely 

 inwards from the centre of the compartments bearing the processes, 

 and conyerging around the latter, on the intervening compartments 

 without order. Processes 5, elliptical, with major axis at right angles 

 to corresponding radius, about 0-01 mm. long, their border broad, 

 striated. Border narrow, hyaline. 



Habitat : Cambridge deposit, Barbadoes (Johnson !). 



C. elega^is Grove & Sturt, Journ. Quek. Mic. CI., 1887, p. 64, pi. v. 



fig. 6. 



Diam. • 0625 to • 0825 mm.. Valves dissimilar, the one with 

 surface subplain or slightly convex from centre to zone of processes, 

 between the latter sloping gently to border. Central space angular 

 to round, from 1/12 to 1/16 of diam. broad. Markings round, 

 granular, towards the centre 6 to 7, near the border 8 in • 01 mm. ; 

 rows uninterrupted, radial, straight, inconspicuous within the processes, 

 secondary irregularly subconcentric rows most evident, on a band close 

 to, and within the processes ; interspaces minute, hyaline. Border 

 distinct, striae delicate, 16 in 0"01 mm. Processes 8 to 11, elliptical, 

 with major axis at right angles to corresponding radius, surrounded 

 by a cuneate hyaline space, with sides slightly convex or straight 

 and symmetrical with respect to the processes. The other valve 

 with surface convex. Central space circular, hyaline, about 1/3 of 

 diam. broad. Markings round, granular, increasing slightly outwards 

 towards central space, 8 to 10, towards border 6 in O'Ol mm., rows 

 radial, interrupted near border by an irregular hyaline band, beyond 

 this band the markings forming coarse striae. Border distinct, 

 hyaline. Processes absent. — Porodiseus interruptus Grove & Sturt, 

 Journ. Quek. Mic. CI., 1887, p. 67, pi. v. fig. 8 ; Morland, Journ. 

 Quek. Mic. CL, 1887, p. 167. 



Herr E. Weissflog in a letter to Mr. F. Kitton, says that he has 

 been able to confirm Morland's observation of the identity of Graspedo- 

 porus elegans and Porodiseus interruptus. 



Habitat : Oamaru deposit (Grove ! Doeg !). 



Artificial Key. 



1. Compartments not cTiiferentiated. Valves dissimilar, the one 



with, the other without processes. Markings 



small, round, granular; rows radial .. .. elegans 



„ distinct 2 



2. Markings large, areolate, edges of compartments not straight ralfskmus 



„ minute, punctate, edges of compartments straight . . johnsonianus 



ISODISCXTS gen. n. 



Valves circular. Surface almost flat or slightly convex towards 

 border. Colour pale smoky grey, darker at border. Central space 

 large, rounded, and evident, sometimes absent. Markings angular, 

 areolate, without interspaces, in evident sabradial rows converging 



