102 Miscellaneous. 
many remarkable forms of animal life that the great island of Borneo 
has yielded, is certainly not the least remarkable. The insect in ques- 
tion is closely related to the Prisopi*, but is even more profoundly 
modified for an aquatic life ; for it breathes not only in the ordinary 
fashion amongst insects by means of trachez opening by stigmata 
on the exterior of the body, but also by the structures known as 
tracheal gills. From each side'of its body, in fact, along the lower 
margins of the sides of the metathorax, there stand straight out five 
equal small but conspicuous ciliated oval plates, which, when the 
insect is submerged and its stigmata are closed, doubtless serve to 
bring the air that is thus shut up within the body into such intimate 
relation either with the oxygen dissolved in, or with the air in 
mechanical mixture with, the water as to render diffusion and con- 
sequently respiration possible. 
The only other insect known to me in which during adult life 
ordinary aerial respiration and respiration by tracheal gills coexist 
is Pteronarcys regalis, one of the Orthoptera Amphibiotica. 
For this remarkable form I beg to propose the name Cotylosoma 
dipneusticum. 
The insect, which is a female with rudimentary organs of flight, is 
between three and four inches in length. 
Auriferous Sand in the Neighbourhood of the Seychelle Islands. 
By H. J. Carrer, F.R.S. &e. 
Belonging to the late Dr. Bowerbank was a little pill-box partly 
filled with sponge-spicules, and labelled ‘“‘ Dust from the Base of 
Dr. Farre’s Euplectella, 26th Feb. 1857.” This sponge, designated 
by Prof. Owen ‘ Euplectella cucumer,” was stated by Dr. A. Farre 
(in whose possession it is or was) to have been “ given with other 
presents, by the king of the Seychelle Islands, to Captain Etheridge, 
R.N., in acknowledgment of some friendly services, with an intima- 
tion that it was one of the rarest products of these regions” (Trans. 
Linn. Soe. vol. xxii. p. 122); and inferring, from actual experience 
(‘ Annals,’ 1873, vol. xii. p. 463), thatthe “‘ dust ” would be found 
to contain a variety of spicule forms, indicative of so many of the 
sponges that must now live, or have lived, in this locality, it was | 
boiled during stv minutes in strong nitric acid to rid it from all cal- 
careous and soft substances previously to mounting in Canada 
balsam for more deliberate observation with the microscope. Six 
slides were thus made, bearing material of different degrees of fine- 
ness, from the most subtle that could be preserved to the coarsest in 
the box, when it was found to contain, as might have been expected, 
a quantity of sand (for the “dust” came from a mass of sea- 
bottom still held together in the root-spicules or beard of the 
Euplectelia). 
But what was most striking, when this sand (about, perhaps, a 
grain in weight) came to be examined, was the presence of minute 
* For an account of the habits of these animals see Andrew Murray in 
Ann. & Mag. Nat, Hist. 1866, 3rd ser. vol. xviii. p. 265. 
