596 Proceedings of Boyal Society of Edinburgh. [sess. 
C. ludovicianus * Rattray. Janischia ? antiqua , Grim. Van 
Heurck., Syn. Diat. Belg ., pi. xcv. bis, figs. 10, 11. — Diam. *335 mm. 
Surface slightly convex towards the centre. Central space and 
rosette absent. Markings minute, 16 in -01 mm.; rows radial, 
straight, but faint ; oblique decussating rows more evident ; apiculi 
prominent, at intervals of ’01 to '015 mm., forming a circlet at a 
distance of *03 mm. from the border ; at opposite sides of the valve 
the apiculi, replaced by a narrow curved hyaline band, bearing 
well-marked radial striae, these bands at a somewhat greater distance 
from the border, and sometimes interrupted ; close to the border a 
circlet of minute apiculi at intervals of ‘005 to '0075 mm., and 
recognised only with difficulty. 
The specific name antiquus cannot be adopted, being preoccupied 
for a distinct form. 
Habitat. — Jutland, Cementstein (Deby !). 
C. polurrliaptos ,f sp. n. — Roundly elliptical. Major axis *1125 
mm., about If- times the minor. Surface with two obtusely conical 
elevations, most evident and meeting at, the centre thence diverg- 
ing and becoming more faint in outline towards the border, 
symmetrical with respect to the minor axis; their outer ends 
embracing about \ of the circumference. Central space and rosette 
absent. Markings hexagonal, most evident at the centre ; towards 
the centre 10 to 12, towards the border 14 to 16, in *01 mm.; rows 
straight ; secondary oblique rows obscure ; minute subulate spaces 
opposite the origin of the shorter rows towards the centre ; apiculi 
evident, scattered irregularly over the surface. Border sharply 
defined, hyaline. — (PI. III. fig. 4.) 
Cyclotella Castracanei, Eul. MS., as noted by Kitton, shows some 
affinity to this species in the lobes about the centre, but in the 
former these lobes do not meet at the centre. The valve marking 
is also distinct. 
Habitat. — Santa Marta deposit, Cal. (Doeg !). 
Grunow refers, in a note to Mr E. Grove, dated May 8, 1888, to 
a species which he names C. Jlorescens, Grun. This, according to 
* Named in honour of Mr Louis Deby. 
t TToAvppcnrTos, embroidered. 
