198 
ZOOLOGICAL LITERATURE. 
which^ on the other hand^ is furnished with tliat process which 
proceeds backwards on the inner side of the orbit. Neither this 
latter process nor that of the frontal with whieh it unites has 
any homologue on the other side of the skull^ or in the skull of 
any other fish. The arrangement of the mueous canals on the 
head is essentially the same as in other fishes. The suborhital 
braneh, however, of the blind side remains behind, while its eye 
has passed to the other side of the head. The author describes and 
figures the ampnllated condition of these canals on the eyeless 
side of the head of Pleuronectes cynoglossus (Platessa pola) . 
The author then proceeds to point out that the vertebral 
column participates, in several respects, in the asymmetry of 
these fishes ; and, finally, as regards the change of position of 
the upper eye of young Plem*onectoids, he comes to nearly the 
same conclusion as Prof. Thomson, viz. that Prof. Steenstrup^s 
views are not confirmed by the anatomical examination of the 
skull of the adult, that the upper eye preserves its morphologi- 
cal relations to the frontal bones and the neighbouring struc- 
tures quite intact, and that the dorsal fin advances on the head 
with the growth of the young fish, as stated by Van Beneden. 
He concludes that Prof. Steenstrup’s specimens* certainly open 
up the question whether there be any group of fiat fishes in 
which, in the normal course of development, the dorsal fin 
extends forwards and bridges over the upper eye before it has 
completed or even commenced its turn : which remark, in the 
Recorder's opinion, contains tlie explanation of the apparently 
contradictory observations of the zoologists mentioned. The 
author remarks that he had arrived at these conclusions before 
he became acquainted with Prof. Thomson's paper. 
Hippaglossus vulgaris extends to the south-western coast of Spitzhergen. 
Malmgren, (Efvers, Svensk. Vet.-Akad. Fork. 18G5, p. 627. 
Ilippoglossoides 2 ilatessoides. Two young- examples, probably belonging to 
this species, were found in Spitzhergen by fir. Malmgren, OEfvers, Syensk. 
Vet.-Akad. Fcirb. 1865, p. 625. 
Ziugopterus. Prof. Steenstrup has discovered a large opening in the me- 
dian septum between the gills of both sides in Pliomhus megastoma, 11. car- 
dina (Fries), P. punctatus (Bl.), and P. imimacidakcs ; and regarding it as a 
g-eneric character, be unites them into one genus, for which he adopts the 
name Zeugapterus (Gottsche). He criticises the Recorder’s aiTangement of 
these fishes, correcting the erroneous statement that P. unimacidatus has 
five branchiostegals (instead of seven), and comes to the conclusion that 
the characters on yf\\\dii^Phry norhombus 2indi^Lepidorhomhus have been 
* The Recorder has lately examined young examples of Pleuronectoids, col- 
lected by Col. Playfair in the African parts of the Indian Ocean, which show 
structurally groat alfinity to those examined by Prof. Steenstrup. lie con- 
siders them to be the young of Phomboidichthys. 
