1888-89.] Mr John Rattray on tlic Genus Coscinodiscus. 655 
ments pale buff. Markings : rays straight, narrow, meeting near 
centre the inner ends of the intercompartmental areas, their outer 
ends knob-like, and reaching about f- of radius from centre; the 
compartments extending to about semiradius, their inner ends 
convex, inwards ; the intervals attenuating slightly outwards, their 
outer ends swollen knob -like, reaching close to the border. — Grev., 
Trans. Micr. Soc. Lond ., 1860, p. 124; Ralfs in Pritch . Inf., 
p. 838. 
One of the intercompartmental areas is more developed than the 
others at its inner end, but the outer portion of the same area is 
not subobsolete,“as is usual in Aster omphalus. 
Habitat. — Elide guano (Johnson). 
§ 2. Centrales. 
Clear, median portion of valve not markedly excentric. Rays 
straight, arcuate or geniculate ; compartments with inner ends 
concave or convex towards centre, sometimes transversely or 
obliquely truncate ; intervals rarely markedly expanded towards their 
outer ends. 
Asterom. wallichianus. Ralfs in Pritch. Inf., p. 837. — Rarely 
roundly elliptical. Diam. *0375 to *055 mm. Centro-lateral area 
Y-shaped. Markings: rays 5 or 6, straight, diverging" from centre; 
the compartments reaching to about semiradius, their inner ends 
transversely truncate or slightly concave towards centre ; the con- 
cavity subconcentric with the circumference ; the areolae distinct ; 
the intervals of uniform width, extending close to border; the 
subobsolete interval attenuating rapidly outwards. — Cleve, Bih. k. 
Sv. Vet.-Ak. Handl. Stockh.,\ 1873, Bd. 1, No. 11, p. 5, pi. i. fig. 1 ; 
Asterolampra wallichiana , Grev., Trans. Micr. Soc. Lond., 1860, 
p. 115, pi. iv. fig. 11. 
Eaint lines pass towards the centre on the interradial spaces 
from the inner angles of the compartments. 
Habitat. — “Bermuda tripoli ” (E. W. Dallas); Nottingham 
deposit, Maryland (Greville!); Santa Monica deposit (Hardman!).* 
Astreom. variabilis, nov. Asterolampra variabilis. Grev., Trans. 
Micr. Soc. Lond., 1860, p. Ill, pi. iii. figs. 6-8. — Diam. *07 to *125 
In the collection of Mr Julien Deby. 
