1888-89.] Mr John Rattray on the Genus Coscinodiscus. 499 
(Grunow); Baltic Sea (Grunow); Tindingen (Cleve !); San Benito 
deposit, California*? (Grunow!?). 
Yar. davisiana. Grun., Denk. Wien. Ak ., 1884, p. 81, pi. iii. 
(C), fig. 19. — Diam. *035 mm. Markings larger, hexagonal, 10 in 
•01 mm.; fasciculi less evident, secondary oblique rows more indis- 
tinct ; apiculi closer to the border, arranged in two concentric rows. 
Habitat . — Davis Straits, Franz Josefs Land (Grunow). 
Yar. intermedia. Grun., ibid., 1884, p. 81, pi. iii. (C), fig 25. — 
Diam. *06 mm. Markings in evident fasciculi, the secondary 
oblique rows distinct ; apiculi distinct, less numerous, at some 
distance from the border, forming a single row, and inserted at the 
middle of and between the fasciculi. 
Habitat . — Cape Wankarema, N. Siberia (Grunow). 
Var. baltica. Grun., ibid., 1880, No. 2, p. 112. — C. polyacan- 
tlius, Grun., Sitzungsb natnrw. Ges. Isis, Dresden, 1878, p. 125. — 
Diam. -03 to '1 mm. Central space minute and irregular, some- 
times distinct, about of diam. broad, having minute isolated 
granules. Markings somewhat larger, rows fasciculate, 12 to 14 in 
*01 mm., straight and regular; apiculi some distance from the 
border, of variable size, especially among larger specimens, arranged 
usually in two subconcentric indistinct rows. — Cleve and Moller, 
Diat., No. 237; C. poly acanthus, var.? baltica, Grun., ibid., 1884, 
p. 81, pi. iii. (C), figs. 17a, 5; C. balticus, Grun., in Cleve’s Coll. 
Though this var. was originally named C. poly acanthus in 
1878, it remained imperfectly defined, C. poly acanthus being sub- 
sequently diagnosed from Jamal valves ; the original C. poly acanthus 
being at the same time (1880) reduced to var. baltica. 
Habitat. — Waxholm, Hernosand; Rathan, Baltic Sea (Cleve! 
Grunow); Baltic bottom clay, black clay from Roslagen, silt from 
Ronneby, Dalaro, Furusund, Norrteljie (Juhlin-Dannfelt). 
C. divisus. Grun., Sitzungsb. naturw. Ges. Isis, Dresden, 1878, p. 
125. — Diam. -08 mm. Central space indistinct, rounded, with 
numerous isolated granules, about ^ of diam. broad. Markings 
round, granular about the central space, elsewhere polygonal; about 
10 in -01 mm., decreasing slightly outwards, on a distinct band 
