1888-89.] Mr John Rattray on the Genus Coscinodiscus. 489 
I have not seen C. curvatulu-s , var. barbadensis , Cleve MS., from 
Barbados, nor C. curvatidus , var. Cleve MS., from Yokohama. 
C. curvatidus , var. frigida , Grun. ( Vega Exped., Vetensk. Jakttag. 
Stockh ., Bd. iii. 1883, p. 488), remains undefined. Specimens so 
named were procured in Franz Josefs Land. 
C. crenulatus, Grun. Sch., Atl. , pi. lvii .fig. 38. — Diam. *0605 mm. 
Central space absent. Markings polygonal, subequal, about 5 in 
'01 mm.; irregular on a small area at the centre, elsewhere in 
fasciculate rows ; those composing the fasciculi parallel to that at 
their corresponding sides; apiculi distinct, inserted at inner edge of 
border and interfasciculate. Border sharply defined, its outer edge 
crenate, the indentations corresponding in position to the spines, 
its inner half with distinct striae 6 in *01 mm., its outer half smooth. 
— Grun., Denk. Wien. Ak ., 1884, p. 83, pi. iv. (D), fig. 17. 
Habitat. — Seychelles, Bolivian guano, ex Salpa spinosa , Southern 
Ocean, Balearic Islands (Grunow); Kings-Mill Islands (Schmidt). 
G. ceginensis. Sch., Atl., pi. cxiii. figs. 13, 14. — Diam. *061 to 
•085 mm. Surface flat. Central space subcircular, to of diam. 
broad, bearing a few isolated round granules, one much larger than 
the others. Markings around the central space round, subequal, else- 
where polygonal, increasing outwards to about the semiradius, thence 
decreasing gradually to the border ; towards the centre 4J, at the 
semiradius 3J in *01 mm.; rows radial, subfasciculate beyond 
the semiradius, secondary oblique rows evident. Border narrow, 
striae 6 in ’01 mm. 
Habitat. — Aegina (Schmidt). 
C. simbirskianus. Grun., Denk. Wien. Ak., 1884, p. 81. — Diam. 
’1 to *225 mm. Central space absent, sometimes minute; rosette 
inconspicuous or subobsolete, sometimes distinct. Markings 
hexagonal, increasing slightly outwards to about the semiradius, 
thence decreasing gradually to the border ; towards the centre 4, at 
the semiradius 3 to 3J, at the border 6 in ’01 mm.; central papillae 
evident; rows fasciculate, those in each fasciculus subparallel to 
that at its centre ; oblique decussating rows evident. Border 
narrow ; striae 4 to 5 in '01 mm. — Sch., Atl., pi. cxiii. figs. 11, 12. 
