108 
Greville, on Asterolampra. 
nating with them, transparent rays are continued from the 
hyaline area between the segments to the margin. 
Section I. — Rays equal and equidistant : Asterolampra. 
1. Asterolampra Marylandica, Ehr. Umbilical lines simple, 
straight ; areolated segments curved at the base. Diameter 
•0016" to -0080". (PI. Ill, figs. 1—4.) 
Asterolampra Marylandica, Ehr. Berl. Monatsbericlit, 1844, p. 76, 
P]. (June), fig. 10. Bail. Sill. Journ., vol. xlviii, PI. 4, fig. B, 
Kutz. Sp. Alg., p. 129. Pritch. Animalc, p. 320, PI. 14, fig. 33. 
Mic. Diet., p. 71, PI 19, fig. 5. Wall. Trans. Mie. Soe., vol. viii, 
p. 47, PI. 2, figs. 13 (6 rays), 14 (7 rays). Briglitw. Mie. Journ., 
vol. viii, PI. 5, fig. 3 (6 rays), 
A. septenaria, A. S. Johns. Sill. Journ., 2d ser., vol. xiii, p. .33. 
A. impar, Shadb. Trans. Mic. Soc., vol. ii, PI. 1, fig. 14 ('7 rays). 
A. pelagiea, Ehr. Berl. Monatsbericlit (1854), p. 238. (Noticed 
first by Miiller, Abhandl. d. Berl. Akad. 1841, vol. i, p. 232, 
PI. 6, fig. 4, in his Memoir iiber den Bau des Pentacrinus caput 
Medusse (7 rays). 
Hab. Various deposits in the United States (6 to 9 rays). 
West Indies (7 rays), E. K. G. Natal (7 and 11 rays). Shad- 
bolt. Monterey stone (7 rays), Professor Walker- Arnott. 
Indian Ocean, from Salpm (6 and 7 rays), Wallich. Indian 
Ocean soundings, at 2200 fathoms (6 rays) . 
This species is exceedingly variable ; and, notwithstanding 
the number of figures which have been given of it, several of 
which, however, are merely repetitions of each other, I have 
considered it very desirable to ofPer some additional ones, in 
order more fully to illustrate deviations from what may be 
regarded as the typical form, well represented by Ehrenberg^s 
original figure. That author has assumed eight as the normal 
number of the rays, and he is probably correct with reference 
to the frustules found in the American deposits. I believe 
that number to predominate, although specimens with from 
six to nine rays also occur in the same deposits. It is at the 
same time a very curious fact, that in the Indian Ocean 
soundings every example which has come under my notice 
possesses only six rays ; and Dr. Wallich has represented one, 
likewise with that number, obtained from Salpce in the Bay 
of Bengal. While thus the number eight appears to predo- 
minate in the American deposits, and six in the Indian Ocean 
(so far as known), an odd number, seven or eleven, was found 
by Mr. Shadbolt to exist exclusively in a gathering from Port 
Natal. It would be rash from such limited data to conclude 
that these are the prevailing numbers on the coast of East 
Africa ; still it is remarkable, that in the gathering specified. 
