Dr. Burnett on the Development of Viviparous Aphides. 261 
The Far.—lt is said that the blind fishes are acutely sensitive 
to sounds as well as to undulations produced by other causes in 
the water. In the only instance in which I have dissected the 
organ of hearing (which I believe has not been before noticed) 
all its parts were largely developed, as will be seen by reference 
to figures 2and 3. As regards the general structure, the parts do 
not differ materially from those of other fishes except for their 
proportional dimensions. The semi-circular canals are of great 
length, and the two which unite to enter the vestibule by a com- 
mon duct, it will be seen, project upwards and inwards under the 
vault of the cranium, so as to approach quite near to the corres- 
ponding parts of the opposite side. ‘The otolite con- 8. 
tained in the utricle was not remarkable, but that of l 
the vestibule (fig. 3) andwhich is seen in dotted out- te 
line in fig. 2 e is quite large when compared with that tr 
of a Leuciscus of about the same dimensions as the 
blind-fish here described. | nana 
The parts represented in fig. 2 are the olfactory lobes and 
nerves a, the cerebral lobes b, optic lobes ¢, the cerebellum d, the 
Otolite in situ e, the medulla oblongata f, and the eyes 
The parts in figures 2 and 3 are enlarged three times linear 
measurement. 
=—_— 
Arr, XXX.— Additional Note to Researches on the Development 
of the Viviparous Aphides ;* by W. 1. Buryetrt, M.D. 
8enitalia. Among the proper females there were, besides those 
Which were filled with eggs or had already deposited them, other 
Individuals in which the ovaries were but feebly developed, or at 
_ Hast, in which no mature eggs had been formed. An opportu- 
* This volume, page 62. 
