Greville^ on Asterolampra. 
1.21 
a link between the last and tlie present section. In fact^ had 
the two median lines united at the central point instead of 
being carried just round it, it would have been included in 
the last section. In other words, it would have been an 
AsteromphaluSj' instead of a " Spatangidium.'^ The six 
perfect rays are broad^ and equal to the margin, like those of 
De Brebisson^s Spatangidium heptactis. The umbilical lines 
have an angular bend, which is so obscurely developed as to 
be liable to be overlooked ; bat the indication of the bend in 
the median lines, towards the margin of the hyaline area, is 
more conspicuous. When carefully looked for, however, 
they will be perceived without difficulty. I have even suc- 
ceeded in tracing in two specimens very slender ramuli, 
passing from the angles of the bend to the angles at the base 
of the segments, exactly as in Spatangidium heptactis ; 
but to do this requires the most careful adjustment possible, 
and such a management of illumination as to throw the um- 
bilical lines, and ramuli, and edges of the ray cavities into a 
light definition. The umbilical lines, including the median 
ones, are robust, and the ar eolation rather large. The valves 
seem very constant to the characters given, as I have tested 
by an examination of above a dozen specimens. In one only 
did the median lines vary, in becoming widely sub -parallel, 
instead of diverging. Perfect examples are very rare. The 
individual figured is the most perfect, but by no means the 
largest in my cabinet. 
17. Asterolampra Shadholtiana, n. sp., Grev. — Areolated 
segments square at the base ; umbilical lines radiating from 
the arch of the pyriform median lines, with the angular 
bend about the middle ; rays seven, terminating consider- 
ably within the margin. Diameter -OOSl". (Fig. 19.) 
Hah. — Indian Ocean, in soundings obtained bv Captain 
Pullen, in 2200 fathoms. 
Mr. Roper very kindly sent both his accurate drawing and 
the slide containing the valve of this interesting species for 
my inspection ; and I have since been so fortunate as to dis- 
cover a second example for myself, so minutely similar that 
the engraved illustration might have been taken from either 
specimen. It seems to be a really well-marked diatom. Its 
nearest ally is perhaps A. Brookei, from which it is separated 
by the very different median lines, and by the angular bend 
being more in the middle of the umbilical lines. If the 
termination of the rays so much within the margin of the 
valve, and singularly short median ray, prove permanent 
characters, they will serve still farther to distinguish the 
present species. I suspect, also^ that, as in A. Roperiana, 
