8 E. GROVE AND G. STURT ON 



three circles of granules, increasing in size outwards ; from this to 

 the margin ran radiating costse, enclosing large oblong cells, extend- 

 ing at the sides to the margin, but shorter opposite the angles. At 

 the foot of each nodule is a blank space, covered with large granules, 

 resembling those at the centre. Between the radiating costas are 

 double lines of granules. A very beautiful form, which we have 

 much pleasure in naming after the introducer of this deposit. Dis- 

 tance between angles of specimen figured, -0044". A smaller form 

 also occurs, -003" length of sides. (PI. II, Fig, 5.) 



Entogonia Davy ana, Grev. (T? iceratium Davyanum, Grev., " Q. 

 J. M. S.," Vol. ii, n.s., p. 232, PI. 10, Fig. 4).— A variety of this 

 form occurs, in which the transverse lines in the central compart- 

 ment, and the clear spaces at the base of each process shown in 

 Greville's figure are wanting. 



Eunotogramma Weissii, Ehr., var. producta, n. var. Gr. & St. 

 (E. Weissii, Gran., in " Franz. Jos. Land," p. 7, PI. B., Fig. 21-22), 

 — Valve with very prominent, sharply-defined, central projection ; 

 considerably produced towards the ends, and terminating with elon- 

 gated angles. The surface of the valve is covered with scattered 

 granules. Length up to -0088". Breadth at centre -003". (PI. 

 II, Fig. 6. Frustule, Fig. 7.) We have classed this as Eunoto- 

 gramma, following Grunow, but it is totally distinct from E. varia- 

 bile, Gran., which may be taken as the type of the genus. E. Weis- 

 sii has great affinity to the Biddulphiw. 



Aulacodiscus Crux, Ehr. (" Grun. Franz. Jos. Land," p. 17 

 vars. " Schm. Atl.," PI. 33, Fig. 1-3). — Small forms are not unfre- 

 quent up to -0052" in diameter. The smaller forms suggest the 

 var. tcnera, Witt. (" Simbirsk," p. 19, PI. 6, Fig. 10). 



A. Comberii, Arnott (" Pritch.," p. 844). Scarce but typical. 



A.decorus, Grev. ("T. M. S.," Vol. xii, p. 82, PI. 10, Fig. 2). 

 — Rare. Processes six in number. Diameter, -01 2". 



A. Stoschii, Janisch (" Schm. Atl.," PI. 34, Fig. 11 ; Walker 

 and Chase, " New and Rare Diatoms," p. 3, PI. 1, Fig. 2). — Scarce. 

 Corresponding to Walker and Chase's form. Processes seven in 

 number. Diameter up to -02". This form is closely allied to A. 

 inflatus, Grev., or the better known A. formosus. 



A. cellulosus, n. sp., Gr. & St. — Valve covered by radiating, 

 distinctly punctate, irregular hexagonal cellules, with a central 

 rosette of small oblong cellules. Furrows distinct, formed by two 

 parallel rows of cellules running from the central rosette to the 



