444 
TUBE-BLADDERED GROUP. 
on the coasts of the greater part of Europe, has both pectoral fins well developed,, 
and the nostrils of the blind side very narrow; the general colour being dark 
brown, with the tips of the pectoral fins blackish. Large specimens may weigh as 
much as 5 or 6 lbs., and a fish of 9 lbs. in weight is on record. Soles are taken by 
trawling: the best ground in England being along the south coast from Dover to 
Devonshire. The lemon-sole (S. aurantiaca), which is a more southern form, 
ranging from the south of England to Portugal, and living in deeper water, is one 
of a group characterised by one of the nostrils of the blind side being dilated and 
surrounded with a fringe of papillae. It is smaller and wider than the common 
species, and orange or light brown in colour, dotted over with numerous small 
brown spots. Other British species are the banded sole (S. variegata ) and the 
dwarf sole (S. minuta), both belonging to a group characterised by the small size 
of the pectoral fins. The Mediterranean sole (S. monochir ) is peculiar in lacking - 
a pectoral fin on the blind side; while the Japanese sole ( S . jag>onica) is one of two 
species in which both these fins are absent. The common species is shown in the 
left lower corner of the coloured Plate. 
On account of the rudimentary condition of their eyes we must 
Blind Soles. 
not omit mention of the blind soles, which are divided into two 
genera, the one ( Soleotalpa ) characterised by the separation of the median fins, 
which are confluent in the other (Apioniclithys) ; pectoral fins being wanting in 
both. Each genus is represented only by a single species; Soleotalpa coming from 
the West Indies, while the habitat of the other species appears to be unknown. 
The Tube-Bladdered Fishes, —Suborder Physostomi. 
It has been already stated on p. 334 that the whole of the four preceding sub¬ 
ordinal groups of the bony fishes are regarded by Professor Cope as constituting 
but a single suborder (Physoclysti) characterised by the absence of a duct to the 
air-bladder, the separation of the parietal bones of the skull by the supraoccipital, 
and by the pelvic fins being usually thoracic or jugular in position. The group to 
which we now come, including the whole of the remaining representatives of the 
existing bony fishes, differs from the above in that the air-bladder, when present, 
has a duct communicating with the stomach or oesophagus, while the pelvic fins 
are always abdominal in position, and the parietal bones are usually in contact 
with each other. With regard to the constancy and importance of these characters 
of the present suborder, Professor Cope writes that the presence of the duct from 
the air-bladder which characterises it, “ is always associated with an abdominal 
position of the pelvic fins and cycloid scales, and mostly with the presence of the 
precoracoid arch, the entrance of the maxillary bone into the border of the mouth, 
and the non-separation of the parietal bones by the supraoccipital. Yet none of 
these characters are precisely associated at the point of change in each, for there 
are Physostomous fishes with separated parietals and ctenoid scales (some Cyprino- 
dontidce), and there are Physoclysti with abdominal pelvic fins.” In the present 
suborder, with the exception of the first in the dorsal and pectorals, which may be 
ossified into spines, all the fin-rays are soft and jointed. Very different views 
obtain as to the best mode of arranging the families constituting the suborder, and 
