A FOSSIL MARINE DIATOMACEOUS DEPOSIT. 141 



arranged in close radiating lines. Processes (in the only specimen 

 observed) seven in number, small, but conspicuous, and slightly 

 inflated, arising from a small hyaline space. Diam. 'QV. (PI. XII, 

 Fig. 33.) 



We are indebted to Mr. Rattray for the discovery of this species. 



A. spectabilis, Grev. (" T. M. S.," Vol. xi, p. 71, PI. 5, Fig. 16). 

 An example of this form has occurred, differing only from Greville's 

 in having four processes instead of five. 



Auliscus projnnquus, n. sp., Gr. and St. — Valve circular, with a 

 clear umbilicus, and two large mastoid processes close to the margin 

 of the umbilicus. Markings granulose in curved lines, with brilliant 

 puncta interspersed, diminishing in number as they approach the 

 margin. Within the margin is a ring of larger puncta. Diam. 

 •0022". (PI. XII, Fig. 34.) 



We are indebted to W. J. Gray, Esq., M.D., for the discovery 

 of this beautiful Auliscus. 



A. lacunosus, n. sp., Gr. and St. — Valve large, slightly oval, 

 with large mastoid processes close to the margin, at the base 

 of which on the inner side is a crescent-shaped clear space or lacuna. 

 Markings very similar to those of A. punctatus, Bail. Diam. *0023". 

 This form is not infrequent in the deposit. We figure a some- 

 what abnormal specimen. (PL XII, Fig. 35.) 



A. lineatuSj n. sp., Gr. and St. — Nearly circular, with a clear 

 lozenge-shaped umbilicus, mastoid processes large, circular, or in 

 some instances somewhat pear-shaped, seated on triangular raised 

 spaces, the apices of which project inwards. Markings scabrous, 

 resembling those of A. hardmanii, but differing entirely in the pre- 

 sence of three diverging ridges or elevations, showing lines on each 

 side of the centre. Diam. to -005". The form figured has circular 

 processes. (PI. XII, Fig. 36.) 



A. inflatus, n. sp.. Gr. and St. — Valve circular, with clear cir- 

 cular umbilicus. Processes large, mastoid, seated at the extremi- 

 ties of a prominent inflation extending along the diameter of the 

 valve. Markings consisting of fine lines with interspersed puncta ; 

 a set of curved lines converge from the centre towards each process. 

 Diam. 0034". (PI. XIII, Fig. 37.) 



We are indebted to L. Hardman, Esq., for the discovery of this 

 very fine form. 



Monopsia, n. gen., Gr. and St. — Valve with discoid outline 

 inflated, the inflation ending in a single mastoid process consider- 



