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 Ibs., and a fish of 9 Ibs. 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 (8. 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 (8. variegata) and the 

 dwarf sole (8. minuta), both belonging to a group characterised by the small size 

 of the pectoral fins. The Mediterranean sole (S. mnonocliir) is peculiar in lacking 

 a pectoral fin on the blind side ; while the Japanese sole (8. japonica) 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 

 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 (Apionichthys) ; 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, w r hile 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 



