Botany and Zoology. 285 
d 
to whose industry and zeal in using it, we are indebted for these and 
many other treasures of the deep. 
5th. The specimens contain a considerable number of the siliceous 
spicules of sponges, and of the beautiful siliceous shells of the Polycis- 
tine the latter I have noticed Cornatella clathrata Ehr., a 
ndings. I have also noticed 
in all the soundings (and shall hereafter describe and figure) several 
species of Eucyrtidium, Halicalyptra, Perichlamidium, Stylodictya and 
many others, 
have not been able to detect even a fragment of any of the 
calcareous shells of the Polythalamia. This is remarkable for the 
striking contrast it presents to the deep soundings of the Atlantic 
whieh are chiefly made up of the calcareous forms. This differen e 
can not be due to temperature as it is well known that Polythalamia 
are abundant in the Arctic seas. pests 
7th. These deposits of wgicroscopic organisms, in their richness, 
genera, however, are not exclusively polar forms, b 
r ut, I 
cently determined, occur also in the Gulf of Mexico, and along the Gulf 
Stream. 
8th. The perfect condition of the organisms in these soundings, and 
the fact that some of them retain their soft portions, indicate that they 
Were very recently in a living condition, but it does not follow that 
they were living when collected at such immense depths. As among 
Brooke 
de 
em ready for publication. 
