Greville^ on Asterolampra. 
119 
14. Asterolampra imhr'icata. — Areolated segments^ sharply 
curved at the base, less than half the radius ; rays numer- 
ous, robust ; angular bends of the umbilical lines forming 
unitedly an oblong elliptical figure. Diameter "0024" to 
•0034"." (Fig. 17.) 
Asteromphalus imbricatiis, Wall., Trans. Mic. Soc, vol. viii, p. 46, 
fig. 9. 
Hah. — Salp(B, Bay of Bengal, Dr. Wallich. Soundings 
from the Indian Ocean, in 2200 fathoms, made by Captain 
Pullen. Natal, Mr. Roper. 
One of the most distinct and beautiful species I am ac- 
quainted with. The appearance of the valve is singularly 
rich, the usual parts being so arranged as to present suc- 
cessive series of radiations. The umbilical lines are given 
off from the top and sides of the median lines in such an 
equal, symmetrical manner that the angular bends are in 
close and parallel approximation. The oblong-elliptical line 
thus formed, taken at its widest part, is about a third of the 
radius, and constitutes what may be called the first zone in 
the radiation. The continuation of the umbilical lines to 
the base of the segments, taken along with the enclosed 
basal portions of the rays, forms a second zone ; and the 
narrower portion of the rays, with the areolated segments, a 
third zone. As all the specimens which I have examined 
differ somewhat from Dr. Wallich^s figure, I have thought it 
desirable to give a supplementary one, of a valve with 
twenty- one rays. I have another drawing of an equally 
perfect valve, with seventeen rays, in all respects similar. In 
'^y valves the median lines taper down beautifully to the 
median ray, and exhibit an abortive angular bend at the 
proper place. The most material difference, however, 
between Dr. WallicVs figure and my specimens consists in 
the wide space represented by him between the two lowest rays 
and the median ray ; whereas in my extensive series of valves 
there is no greater space than there is between any of the 
other rays ; indeed, in most frustules, the space is rather 
less. The outline of the valve is slightly, but perceptibly, 
ovate ; the areolation considerably larger than in A. elegans, 
its nearest ally. It is the most robust species which has 
occurred in the Indian soundings, and hence, perfect indivi- 
duals are not quite so rare as in other cases. Among Mr. 
Roper^s drawings is one of a valve from Natal, with only ten 
rays, and in diameter only '001 5". In all material charac- 
ters, however, it agrees well with the present species. 
15. Asterolampra Brookei. — Valve nearly quite circular; 
