XIX.—A Revision of the Flat-fishes (HETEROSOMATA) of Natal, 
by 
C. Tate Regan, M.A., F.R.S. 
(Published with the permission of the Trustees of the British Museum), 
HE Flat-fishes differ from all other fishes in having both eyes on 
the same side of the head. ‘The scheme of classification given 
below differs slightly from mine of 1910 (Ann. Mag. Nat. Hist. [8], 
VI, pp. 484-496) in the recognition of the Pleuronectoidea and 
Soleoidea as equal in rank to the Psettodoidea and in making 
Paralichthodes the type of a new family. Specimens of this interesting 
genus now received from Durban have enabled me to examine its 
structure and it proves to be unique amongst dextral Pleuronectoidea 
in the structure of the nasal organ, which is like that of the sinistral 
Pleuronectoidea and of Psettodes and the Soles. 
Orver HETEROSOMATA. 
Susp-orpER 1. PSETTODOIDEA. 
Psettodes. W. Africa; Indo-Pacific. 
SuB-oRDER 2. PLEURONECTOIDEA. 
Family 1. Boruipa. 
Sub-family 1. ParaxicutHins&. ‘Tropical and Temperate Seas. 
* 2. Bornine. Tropical and Temperate Seas. 
3. Pservine®. N. Atlantic. 
Family 2. ParaLicHTHoDID&®. 
Paralichthodes. S. Africa. 
(205) 
Annals of the Durban Museum, Vol. II, part 5, issued 25th March, 1920. 
