1888-89.] Mr John Rattray on the Genus Coscinodiscus. 571 
Yar. Woodivardii , Rattray. C. Woodwardii, Eul., Diat. Spec. 
Typ ., No. 116. — Diam. *1075 to *15 ram. Central space small, 
sometimes absent ; rosette usually distinct. Markings polygonal, 
subequal, or increasing slightly outwards, again decreasing near the 
border ; towards the rosette 4, at about f of radius 3, in -01 mm.; at 
the border much more minute. — C. Woodwardii , Eul.; Sch., Ail., pi. 
lxi. fig. 3 (not fig. 2); G. apiculatus , var. ambigua , Grun., Denh. Wien. 
Ah., 1884, p. 75; G. perforatus, Cleve and Moller, Diat., No. 57. 
Specimens in Chincha guano are transitional to C. Janischii. 
Habitat. — N. American tertiary deposits, mouth of the Maranhon, 
Cuxhaven (Grunow, Firth !) ; Virginia (Hardman !) ; Monterey 
(Moller!); Mejillones, Bolivia (Firth!); trawled in lat. 24° 42' 
N., long. 152° 1' W., by H.M.S. Challenger (Rae !) ; Piscataway 
deposit (Rogers !) ; * Rappahannock, Ya. (Rogers ! * Eailey !) ; Ber- 
muda tripoli (Greville!); Delaware, Md. (O’Meara!); Richmond 
tunnel (O’Meara !) ; Richmond (Cleve and Moller!); Oamaru 
deposit (Grove !) ; Whampoa (Grove !) ; Chincha guano (Grove !) ; 
Lobos di Afuera guano (Grove !) ; Upper Peruvian guano (Weiss- 
fiog !) ; Monterey (Weissflog ! Cleve! Greville! Moller!); Moron 
deposit (O’Meara !) ; Nottingham deposit (Cleve and Moller ! f 
Hardman! O’Meara!); Maryland (Cleve !); Pabillan de Pico guano, 
Holland’s cliff (Cleve !). 
Yar. maxima. Grun., ibid., 1884, p. 76. — Diam. ‘315 mm. 
Central space hyaline, from to ■— of diam. broad. Markings 3J 
to 4, at the border 7, in -01 mm. 
Habitat. — Richmond, Ya. (Grunow). 
C. perforatus. Ehrh ., Mon. Ber. Ah., 1844, p. 78. — Diam. *09 
to -1325 mm. Central space small but distinct, without a surround- 
ing rosette. Markings rounded and granular or polygonal, on the 
same or on different valves, 3J to 4 in *01 mm., somewhat smaller 
towards the border, the central dots obvious ; minute puncta at the 
inner ends of the shorter radial rows. Border striae, 6 in *01 mm. — - 
Ehrh., Mihrog ., pi. xviii. fig. 46; Sch., Atl., pi. lx. fig. 12 (?) ; pi. 
ixiv. figs. 12-14; Smith, Syn. Brit. Diat., ii. p. 85. 
Specimens from Callao seaweeds sometimes exhibit at the 
* In the collection of Dr Greville. 
% t Diat., Nos. 215, 216. 
