DENNIS, ON CETACEAN BONES. 
191 
only the stump of a long cylindrical horn^ standing straight 
out from the centre of the triangular end of the frustule. 
The edges of the end are fringed with a comb-like row of 
papillae or setse. In the same state of the gathering Avere 
also seen individuals having the end view in the form given 
by Professor Smith. 
Trtceratmm striolatum, Eoper^ T. alternans, and T. variable 
were found in the same material^ but the species which seems 
to constitute the principal food of the Noctilucse is the Actino- 
cychis unclulatus, Kutz. It has been found in very great 
numbers in every gatherings and it appears to constitute 
a large proportion of the diatomaceous contents of the 
Noctilucse. 
Living specimens of another form^ which we deem to 
belong to the genus Rhizosolenia of Ehr._, were detected in 
the Noctilucae^ and we have also received from Mr. Norton, 
of Hull, specimens of the same, or a nearly allied species, 
found in an Ascidian, in which Mr. Norton was fortunate 
enough to detect many specimens in a perfect state. 
This species consists of a long transparent tube, having a 
delicate twisted or spiral appearance, running through its 
whole length, as in some of the fresh-water Algae, and at 
either extremity a styliform testule, with bifid branches in- 
serted in the tube. The entire forms, when subjected to 
acid, break up, and leave the siliceous Rhizosolenian frustules 
perfect; but fragments only of the tube are found, in the 
shape of imperfect rings. We propose, under the above 
definition, to give this species the name of R. styliformis. 
AVe hope to be able to give further details of the remark- 
able forms of Diatomaceae found in the Noctilucae in a future 
number of this journal. 
On the Microscopical Characters of certain so-called 
Cetacean Bones associated with Cetolites in the De- 
TRiTAL Bed of the Bed Crag at Felixstow, Suffolk. 
By the Bev. J. B. P. Dennis, F.G.S. 
In the detrital bed at the base of the Bed Crag, especially 
at Felixstow, in the county of Suffolk, are found very singular 
fossils, and in such considerable quantities that they have 
been made available for economic purposes. But while the 
manufacturer of artificial manure is daily grinding down 
heaps of the relics of a former world to renovate the earth. 
