1888-89.] Mr John Rattray on the Genus Coscinodiscus. 453 
C. patina ,* Bail., Amer. Journ. Sci ., 1843, vol. xlii. p. 96, pi. ii. 
figs. 13 a, b. 
Seychelle specimens, '048 mm. diam., have 10 strise in '01 mm. 
on the border. 
Habitat. — Richmond deposit, Ya. (Bailey) ; mud from Elbe, 
at Ouxhaven (Kiitzing); Seychelles, Mauritius, and Tonga 
Islands (Cleve and Grunow). 
C. impolitus , sp. n. C. antarcticus, Cstr. (non Grunow), Diat. 
Chall. Exped ., p.. 157, pi. xii. fig. 10. — Diam. '055 mm. Central 
space absent. Markings punctiform, closely and uniformly dis- 
posed ; apiculi minute hut evident, scattered over the surface at 
wide suhregular intervals. Border narrow, hyaline. 
This species approaches very close to Melosira Borreri , Grev. 
( = M. moniliformis and M. lineata , A g.) (Van Heurck, Syn. Diat. 
Belg ., pi. lxxxv. fig. 7). 
Habitat. — Heard Island, H.M.S. Challenger (Castracane). 
C. insutus, sp. n. Sch., Atl ., pi. lvii. fig. 2 (no name). — Diam. 
'024 mm. Central space absent. Markings punctiform, irregular, 
not crowded ; interspaces wide, hyaline ; a circlet of long narrow 
curved apiculi inserted a considerable distance within border. 
Border broad, sharply defined ; strise robust, 4 in '01 mm. 
Habitat. — Sansego (Schmidt). 
C. granulosus , Grun. Kongl. Sv. Vet.-Ak. Handle Stockholm, 
1880, No. 2, p. 113, pi. vii. fig. 130. — Diam. '016 to '033 mm.; 
Surface not depressed at centre. Central space absent. Markings 
punctiform ; most crowded, largest, and most evident towards the 
centre ; apiculi at the border minute, 3 in '01 mm. Border rela- 
tively broad — about '0025 mm., sharply defined; strise 17 to 18 in 
•01 mm. — Odontodiscus granulosus , Grun., ibid., p. 113. (PI. I. 
fig. 23.) 
This species approaches G. cinctus , Kiitz., hut in the latter the 
central puncta are coarser, the apiculi are absent, and the border 
strise stronger. Einmark specimens have been observed ornamented 
towards the centre with radiating curved faint lines instead of 
isolated granules, thus forming a transition to C. marginulatus. 
Name preoccupied by Ehrenberg iu 1838. 
