STRUCTURE OF THE CRYSTALLINE LENSES OF ANIMALS. 
47 
at right, angles to it, so that in this structure the fibres exhibit no contrariety of flexure, 
as in all the other lenses with septa at each pole. The very same structure appeared 
in the other lens of the same turtle ; and was found likewise in both the lenses of an- 
other turtle, in which the diameter of the eyeball was 1*2 of an inch, and that of the 
lens 023. 
The fibres and their teeth are nearly the same in the turtle as in the lenses of qua- 
drupeds, the teeth being very short, though perfectly distinct. 
The structure represented by figg. 1 and 2 (Plate VI.) is possessed by the lenses of 
the following fishes : 
The Drune. Crocer. Grey Gurnard. 
Bass. Angel Fish. Red Gurnard. 
Whiting from Georgia. Mullet ? from Georgia. 
1. The Drune, or Drum, from Georgia. — The lenses of this fish, along with those of 
the other fishes in the above table, except those of the gurnard, were sent to me with 
their common names by Mrs. Green of Cumberland Island. In both the lenses 
of the drune the different structures were very distinctly seen. The fibres varied 
greatly in diameter as they approached the pole ; and though the secondary colours 
were not visible, yet the teeth of the fibres were beautiful and distinct. 
2. The Bass from Georgia. — In this lens the double arrangement of the fibres is 
distinctly seen. 
3. The Whiting from Georgia. — The same structure is clearly seen in both the 
lenses of this fish. 
4. The Crocer from Georgia. — In both the lenses two short septa are seen in the 
anterior face, and a single pole in the posterior one. The teeth of the fibres are very 
close, but distinct. 
5. The Angel Fish from Georgia. — In the lenses of this fish the two structures are 
very distinct, and also the teeth of the fibres. 
6. Mullet from Georgia. — I am in some doubt respecting the existence of the dou- 
ble structure in the lens of this fish. The observation which I made many years ago 
is thus recorded : “ A sort of diffused polarity round two poles, as if there were two 
septa on each side, like those of the hare, or on one, like that of the turtle.” As a dif- 
fused polarity was the only fact actually observed, I find that I have placed the mul- 
let in the list of fishes without septa. 
7. 8. Red and Greg Gurnard. — In the lenses of both these fishes there were two 
short septa on one side and none on the other. 
In examining the lens of a very large turtle, in which the eyeball was 1*4 of an 
inch in diameter, and that of the lens 025 of an inch, I found to my great surprise 
that there were three septa in front, as in quadrupeds, and four septa, or rather six, 
as in the seal. The following is the account of the observation which I recorded at 
the time : “ I saw distinctly the above septa on both sides when the lens was fresh 
and transparent, and plunged in oil of almonds, and I confirmed this result by boil- 
