536 Proceedings of Boyal Society of Edinburgh . [sess. 
Diat. Belg ., pi. xciv. fig. 24), by the absence of punctiform granules 
on the central space. In Schmidt’s figure of C. vacuus , a minute 
round central areola (nodule?) is faintly indicated. 
Habitat. — Cape of Good Hope (Schmidt). 
C. mesoleius. Cleve, Vega Exped. Jakttag. Stockh ., Bd. iii., 
1883, p. 503, pi. xxxviii. fig. 2. — Diam. -03 mm. Central portion 
hyaline, extending outwards to about § of the radius, sharply 
defined. Markings on outer portion punctiform, 28 in *01 mm., 
forming radial striae. 
The valve is very thin and transparant. It approaches C. 
Hauckii , Grun. (Van Heurck, Syn. Diat. Belg., pi. xciv. fig. 29) ; 
but in the latter the central portion is covered with irregular 
scattered puncta. Both approach the genus Cyclotella. 
Habitat. — Labuan, near Borneo, among Algae* (Cleve !). 
C. lutescens , sp. n. — Diam. *125 mm. Surface flat. Central 
space circular, minute, surrounded by a subobsolete band of large 
cuneate areolae. Markings hexagonal, distinct, increasing outwards 
for about -f- of the radius, thence decreasing to the border ; towards 
the centre 5, at -f- of radius 3J, in *01 mm.; central papillae faint ; 
rows straight, at intervals with the markings oblique; apiculi 
minute, inserted at the border at intervals of about *005 mm. 
Border narrow; striae faint, 8 to 10 in *01 mm. — (PI. II. fig. 2.) 
Distinguished from G. cribrosus, Tru. and Witt, by the gradual 
increase of the markings outwards. 
Habitat. — Jeremie deposit, Hayti (Bae !). 
C. modestus , sp. n. — Diam. *325 mm. Surface flat, becoming 
convex towards the border. Central space round, indistinct, about 
— 3 of diam. broad. Markings delicate and faint for inner § of 
radius, more evident on the outer J, increasing from the central 
space outwards, towards the centre punctiform 8, beyond the semi- 
radius distinctly hexagonal, with evident central papillae, 4 in 
•01 mm.; rows around the central space of unequal lengths, and 
separated by hyaline interspaces, towards the border subfasciculate, 
the fasciculi separated by fossil subhyaline radial lines ; apiculi 2, 
unsymmetrical, separated by an interval equal to about J of the 
Collected by Dr Kjellman. 
