216 Proceedings of the Royal Physical Society, 
eyes has passed bodily through the head, beneath the dorsal 
fin, till it has reached that side where both are now found, 
and where it has formed for itself a new and anomalous 
orbit ; a view which, it must be confessed, grates a little 
against most of our preconceived morphological ideas. 
But from what we see on the outside of the fish, we can 
only rashly speculate. It is only by anatomical and embryo- 
logical research that we can gain an insight into the true 
state of the case. 
As I am looking forwards at no distant date, to the pub- 
lication, elsewhere,* of a detailed account of the osteology of 
the flat-fish head, considered in relation to the asymmetry 
of these fishes, 1 will, in this communication, content my- 
self with a brief review of the theories which have occurred 
to various writers on this subject. And especially I shall 
inquire as to what light embryology, including the exami- 
nation of monstrosities, has as yet afforded us. 
Autenrieth is the oldest writer I have found to allude to 
the subject anatomically, in a paper on the anatomy of the 
Plaice {Platessa vulga^^is), published in the year 1800. f His 
remarks on the osteology of the Plaice are however meagre, 
and his theoretical conclusions will seem to us now-a-days 
absurd ; for he accounts in the following manner for the 
position of both eyes on the right side of the head. He says, 
" The examination of the skeleton shows us that the entire 
left side of the fore part of the cranium is in reality want- 
ing, and that nature, in order not to lose an eye, was necessi- 
tated to put it into the hollow of the right cheek, under the 
alone remaining right orbit." 
Kosenthal (Ichthyotomische Tafeln, Berlin, 1812-22), a 
little more rational in his ideas than Autenreith, held the 
upper eye of the flounder to be that of the left, or now eye- 
less side, but accounted for its getting to the right side by 
its being thrust through the head and getting placed be- 
* Transactions of Linnean Society for 1865. 
t Wiedemann's Archiv fiir Zoologie und Zootomie. Thl. i. 1800, s. 47, et 
seq. " Bemerkungen iiber den Ban der Scliolle {Pleuronectes platessa) ins- 
besonders und den Ban der Fische hauptsachlich ihres Skelets im Algemeinen," 
Von Dr T. H. F, Autenrieth, Prof, der Anatomic in Tiibingen. 
