CHAP. XX.] 
FISHES. 
441 
Seven genera occur in British seas, viz. : Hippoglossus , Hippo- 
glossoides, Rhombus , Phrynorhombus , Arnoglossus , Pleuronectes 
(Turbot), and Solea (Sole). There are 13 genera in the Atlantic 
and 23 in the Pacific, 4 being common to both ; and 2 found 
only in the Mediterranean. A Pacific genus, Synaptura , has 
one species in the Mediterranean. 
Order IK—. PH YSO STOMI. 
Family 59.— SILUBIDriE. (114 Genera, 547 Species.) 
“Fresh-water or marine, scaleless fishes, often with bony 
shields, and the head always furnished with barbels” 
Distribution. — The fresh waters of all the temperate and 
tropical regions, those which enter the salt water keeping near 
the coast. 
This extensive family is divided by Dr. Gunther into eight 
sub-families and seventeen groups, the distribution of which is 
as follows : — 
Sub-family 1 (Silueiil® Homalopterje) is confined to the 
Old World. It consists of three groups : Clarina (2 genera, 
Glarias and Heterobmnchus ) ranges over the whole area of the 
Ethiopian and Oriental regions, to which it appears to be strictly 
confined ; Plotosina (3 genera, Plotosus, Copidoglanis, and Cnido- 
glanis) ranges from the eastern coasts of Africa to Japan, Poly- 
nesia, and Australia, in seas and rivers ; Chacina (1 genus, Chaca) 
ranges from India to Borneo. 
Sub-family 2 (Silurid^i Heteropter^e) is also confined to the 
Old World ; it consists of one group, — Silurina, containing 19 
genera, viz. : — Saccobranchus (4 sp.), India to Cochin China and 
Ceylon ; Silurus (5 sp.), Palaearctic region from Central Europe 
to Japan, China, and Afghanistan, and a species in Cochin China; 
Silurichthys (3 sp.). Cashmere, Java, and Borneo ; Wallago (2 sp.), 
Hindostan, Sumatra, and Borneo ; Belodoniichthys (1 sp.), Su- 
matra and Borneo ; Eutropiichthys (1 sp.), Bengal ; Cryptopterus 
