516 Dr. A. A. Gray. On the Anatomical [June 1, 
one piece, which is bent sharply on itself at its vestibular end, while at the 
distal extremity, in the region of the lagena, the two approach one another 
and become fused into one. The ellipse formed by the two limbs of the 
cartilage is, of course, occupied by the basilar membrane. Furthermore, this 
elliptical cartilaginous framework is curved and also rotated upon itself to a 
certain extent, so that its concavity looks backward and upwards, the structure 
being therefore parallel with the curvature of the cochlea itself. 
In the penguin there is found almost exactly the same disposition of the 
cartilaginous framework as that just described in the rhea. That is to say, 
it does not consist of two plates of cartilage with different points of origin 
at the vestibular end of the cochlea, but of a single piece in the form of a 
long ellipse. At the vestibular and middle portions of the cochlea one of the 
limbs of the ellipse runs along the lower surface of the cochlea and separates 
the oval window from the large opening which gives access to the perilymph 
recess. The other limb runs along the upper surface of the cochlea, and 
through its substance pass those fibres of the cochlear nerve which are 
destined to supply the basilar membrane. Towards the lagena, however, the 
cartilaginous framework becomes rotated to a certain extent upon its long 
axis, so that the lower limb becomes posterior and the upper limb becomes 
anterior ; the two limbs then become fused at the iagena. 
This disposition of the cartilaginous framework within the cochlea of some 
birds is not difficult of explanation when it 1s remembered that in the 
reptiles the basilar macula is supported by a single circular or oval 
cartilaginous ring. The only change in the disposition of the cartilaginous 
framework which has taken place in the transition from the reptile to the 
bird is, that the circular ring has been drawn out into a rather long ellipse. 
Further, a certain amount of rotation round its own long axis appears to 
have occurred. Thus it comes about that in the proximal portion of the 
organ the limbs of the cartilage are superior and inferior, while at the 
lagenar end they are posterior and anterior. 
The disposition of the cartilaginous framework in the cochlea of the bird 
is well seen in the photograph of the Cape gannet, and is undoubtedly the 
arrangement found in many other birds.* 
With respect to otoliths in the labyrinth of the penguin, no conclusions can 
be drawn from the specimen obtained by the writer. It had lain for several 
years in spirit, and it is quite possible that the calcareous otoliths had been 
dissolved by some chemical agent produced during the long immersion in that 
fluid. 
Pigment appears to be entirely absent from the labyrinth of the penguin ; 
* Gray, op. cit., vol. 2, p. 134. 
