TRANSACTIONS OF THE SECTIONS. 135 
appearance of an outer and an inner circle in the iris was seen, but no 
muscular fibres: the delicate membrane described by Jacob on the 
posterior surface of that body, he found to be reflected from its 
external circumference to the fore part of the hyaloid membrane, 
which it accompanied to the capsule of the lens. The choroid mem- 
brane, single in front, is double posteriorly, inclosing between its 
layers the choroid body, which was supposed to consist of erectile 
tissue, and to enable the eye to adjust itself to vision at different dis- 
tances. The ciliary processes are wanting. The retina extends from 
the optic nerve to where the choroid membrane forms a continuity 
with the iris. The humours are similar to those of other fishes; and 
in examining the fibres of the lens with the microscope, the serrated 
appearance described by Sir David Brewster was seen. The organ of 
hearing consists of a lower and upper sac, and three semicircular tubes ; 
the sacs are lodged in the interior of the skull, and the tubes con- 
nected with the upper, in canals formed partly of bone and partly of 
cartilage. The interior is filled with fluid, and in each sac there is a 
dense calcareous mass or otolite; that in the upper being small and 
round, that in the lower large and triangular. The auditory nerve 
divides into a number of branches distributed to the sacs and canals. 
On the various Modes of Fishing employed by Indians in the 
West of Guiana. By M. ScuHomsBurek. 
Although the Ichthyology of South America be little understood by 
European naturalists, yet the native Indians are practically well ac- 
quainted with the various tribes that are found in the magnificent 
streams of the New World. An acquaintance with about eighty 
species has thus been made by M. Schomburgk. The Indians in 
their fishing excursions use canoes, which are propelled and directed 
by paddles in a peculiar manner. The canoes on the Essequibo are 
mostly formed of a hollow tree, and small corials are used formed in 
the same manner. Another kind of boat is also used, called a pakasse, 
and formed out of the bark of a tree. “ When we ascended the river 
Berbice,” says the author, “two Wauawai boys belonging to our party 
navigated one of those pakasses. They were perhaps not more 
than eight years old, but we were highly delighted to see how ably 
they managed it. The boat seemed to fly through the water, and the 
juvenile steersman directed its course with such judgment and precision 
that it never grounded, though it went over places where there were 
not more than eight or nine inches of water. They were equally ex- 
pert in the use of the bow and arrow; and, wherever they observed 
one of the finny tribe, the pakasse was halted, the bow strung, and off 
flew the pointed arrow, and when taken out of the sand, which the 
water barely covered, we generally observed a fish struggling for 
liberty.” After describing the descent of the rapids, in which these 
rivers abound, and the appearance of a band of travellers halting on 
the shores of the river, he adds, “ During night commenced the fishing 
