1888 - 89 .] Mr John Rattray on the Genus Coscinodiscus. 549 
C. asteromphalus. Ehrb., Mon. Ber. Ak., 1844, p. 77. — Diam. 
*085 to '3 mm. Surface slightly depressed at the centre, and 
convex towards the border. Central space small, obtusely angular, 
surrounded by a distinct rosette. Markings polygonal, robust, 
punctate, 3J to 4 in *01 mm., increasing slightly towards the 
border to 2J or 3 in ’01 mm.; central dots distinct. Border 
distinct; striae obvious, coarse, about 4 in *01 mm. — Ehrb., Mikrog ., 
pi. xviii. fig. 45 ; pi. xxxiii. 15. fig. 7 ; Ralfs in Pritch. Inf., p. 828; 
Grun., Denk. Wien. Ak ., 1884, p. 78; Pant., Fossil. Bacil. Ung ., 
p. 71; Sell., Atl ., pi. cxiii. fig. 23; Van Heurck, Typ. Syn. Diat. 
Belg., No. 508; Cleve and Moll., Diat., Nos., 57, 164 ; Janiscb, 
Gazelle Exped., taf. iv. fig. 9 ; C. asteromphalus, var. genuina , 
Grun., Denk. Wien. Ak., 1884, p. 78 ; C. asteromphalus, var. 
conspicua, Grun.; Van Heurck, Syn. Diat. Belg., pi. exxx. figs. 1, 
2, 5, 6; Grun., Denk. Wien. Ak., 1884, p. 78 ; sp. n. 1 Sell., Atl., 
pi. lxiii. fig. 5. 
This species is distinguished by the evident puncta on the 
markings. Grunow has observed in Richmond specimens a finely 
punctate layer detached. The places corresponding to the angles 
of the markings have coarse, mostly triangular dots, the round 
central dots are only found in perfect valves. 
Habitat. — Richmond (Ehrenberg, Cleve and Moller !) ; and Holies 
Cliff deposit, Va. (Ehrenberg) ; guano (Grunow) ; Sta Monica 
deposit (Weissflog! Rae !) ; Fernando Noronha guano (Rattray !) ; 
New York, in the sea (Grunow) ; Arica (Schmidt). 
Var. eximia, Grun., ibid., 1884, p. 78. — Diam. '475 mm. Central 
space irregular, small. Markings increasing slightly outwards from 
central rosette to about f of radius, 2 to 2J in '01 mm. — C. aster- 
omphalus, Ehrb; Sch., Atl., pi. lxiii. fig. 12. 
Habitat . — Santa Monica deposit (Schmidt, Rae ! Deby !). With 
type (Grunow). 
Var. omphalantha. Grun, ibid., 1884, p. 78; C. omphalanthus, 
Ehrb., Mon. Ber. Ak., 1844, p. 266. — Diam. *255 to '45 mm. 
Central space sometimes absent, rosette conspicuous or less obvious. 
Markings subequal to about of radius, 2J in '01 mm., thence 
decreasing gradually to the border, sometimes slightly smaller 
towards the central rosette. Border somewhat sharply constricted 
