656 
Proceedings of Royal Society of Edinburgh. [ sess . 
mm. Centro-lateral area Y-shaped, with inner end obtuse or sub- 
acute, sometimes reaching the centre. Markings : rays substraight 
or somewhat curved, well-defined, frequently dichotomous, sometimes 
meeting in a small semicircular line curving round the centre ; the 
•compartments reaching from f to f of radius inwards, their inner ends 
obliquely truncate, on each side of rays straight or slightly concave 
towards the centre ; areolae distinct, decreasing gradually outwards 
from 5 to 8 in *01 mm.; the intervals straight or slightly arcuate, their 
outer ends convex outwards, sometimes hardly reaching the border. 
Habitat. — Monterey stone (Greville ! Arnott ! Kitton!);* Santa 
Monica deposit (Grove !). 
Asterom. Hookerii. Ehrb., Mon. Ber. AJc ., 1844, p. 200, pi. 
(June) fig. 3. — Diam. *064 mm. Centro-lateral area with sides 
straight, parallel or slightly concave outwards, sometimes suddenly 
contracting near the subobsolete interval, its inner end conical. 
Markings : rays straight ; the compartments reaching from J to ts- 
of radius inwards, their inner ends rounded ; areolae delicate ; the 
intervals attenuating slightly outwards, reaching the border. — Ehrb., 
Mikrog., pi. xxxv. a. 21. fig. 2 ; Ralfs in Pritch. Inf., p. 836, 
pi. xi. fig. 34; A. Buchii , Ehrb., ibid., 1844, p. 200, pi. (June) 
fig. 4, — 7 rays ; A. Cuvierii , Ehrb., ibid., 1844, p. 200, pi. (June) 
fig. 7, — 9 rays; Mikrog., pi. xxxv. a. 21. fig. 1 ; Janisch, Abh. Schl. 
Ges. voter. Cult., 1861, p. 160 ; A. Humboldtii, Ehrb., ibid., 1844, 
p. 200, pi. (June) fig. 6, — 8 rays; Mikrog., pi. xxxv. a. 21, fig. 3; 
Janisch and Rabenh., Beitr., p. 4, pi. iii. fig. 11 ; Sch., Atl., 
pi. xxxviii. figs. 18-20 ; Asterolampra Hookerii, Grev., Trans. Micr. 
Soc. Bond., 1860, p. 114. 
Habitat. — Pancake ice, Antarctic Ice Barrier, lat. 78° 10' S., 
long. 162° W.; lat. 75° S., long 170° W.; lat. 64° S., long. 160° W. 
(J. D. Hooker); Peruvian guano (Janisch); H.M.S. Challenger, lat. 
53° 55' S., long. 108° 35' E., 1950 fathoms (Grove ! Rae !). 
Asterom. shadboltianus. Ralfs in Pritch. Inf., p. 838. — Diam. 
*0775 mm. Centro-lateral area ovate, attenuating rapidly towards 
its outer end, angular at the centre. Markings : rays 5, straight, 
or with a small geniculation near their middle ; the compartments 
reaching about J- of radius inwards, their inner ends transversely 
* In the collection of Dr R. K. Greville. 
