928 
ME. A. SANDERS ON THE ANATOMY OF THE 
brain in these Fishes. He supposed that they had a Mammalian cerebrum ; the pink 
colour and the minute striations of the surface, which superficially resemble convolu¬ 
tions, led him into this error. 
Marcusen went more thoroughly into the subject; but even he, in his first* * * § paper, 
was of the same opinion. 
About this time Ecker t wrote a description of a brain of a very small species, pro¬ 
bably a young Mormyrus Cyprinoides; the conclusion he came to was, that the highly- 
developed organ which is the subject of this paper, was the corpus quadrigeminum. 
Eleven years after the first slight sketch referred to above, Marcusen J took a view 
of the brain of this Fish more nearly approaching the truth, inasmuch as he supposed 
that the “ Eigenthiimliches Organ,” as he termed it, was part of the cerebellum. 
Oefeinger,§ whose paper, so far as I know, was the last that has been written on 
this subject, added nothing to the information possessed by his predecessors. 
These Fishes are by no means easily procured by ordinary tourists on the Nile. 
Y. Miklucho-Maolay || has placed it on record that he was unable to see one 
during his stay in Egypt. He appears to have been there twice, but his residence 
each time must have been short; else his great powers as a traveller would surely have 
come to his assistance in this, as in other matters. 
I was more fortunate, and by enquiring of native fishermen, through the medium 
of my dragoman, succeeded in obtaining a sufficient supply of living specimens. 
The two species which I obtained most abundantly were, Hyperopisus dorsalis 
(Gunther), which was described by Marcusen under the name of Phagrus dorsalis , 
and Mormyrus oxyrhynchus, but this latter was much more rare than the former. 
Of a species of Mormyrops I obtained one or two specimens. 
The mode of procedure which I adopted in the treatment of the brains of these 
Fishes was the following. Ail sensation, or at least all sensation of pain, having been 
eliminated by section of the spinal cord at, or nearly opposite the region of the 
pectoral fins, parts of the top or sides of the skull together with the facial bones and 
ail superfluous tissue were removed, and the skull containing the brain was placed in 
Muller’s fluid and spirits of wine in the proportion of one-third of the latter to 
two-thirds of the former. This solution was changed the next day, and again in 
three or four days, one more change was made at about the tenth day, and after 
being in this fluid for three weeks, the brain was removed into a 2 per cent, solution 
of potass-bichromate. The potass-bichromate was changed once a fortnight. It is not 
absolutely necessary to change the solution so often ; the more frequently it is renewed, 
* Gaz.Med. de Paris. Sur quelques particularity des Mormyrus, 18S3, p. 136. Also Bull, delaclasse 
Pliys. Math, de l’Acad. Imp. des Sciences de St. Petersbourg, tom. xii., 1854. 
f Anatomische Beschreibung des Gehirns vom Karpfenartigen Nilhecht. Leipzig, 1854. 
| Loc. ait. 
§ Neue Untersuchungen ii. d. Bau d. Gehirns vom Nilhecht. Arch. f. Anat., 1867. 
|| Beitrlige z. vergleichenden Neurologie d. Wirbelthiere, p. 69, note. 
