90 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



entertain no doubt that this su^jposed mark is only 

 of casual occurrence, and may as well be met with 

 in one species as the other ; as it is not uncommon 

 also in the Turbot, Brill, and, as we shall presently 

 see, in the Megrim or Scald-fish." So that this dis- 

 tinction cannot be relied upon according to Couch. 

 On the other hand, while our fish in no degree 

 resembles the drawing in Couch of Block's Top-Knot, 

 P. unimaculatus, Gun., yet the ventral and anal 

 fins are distinctly separated one from the other. In 

 this connection Couch remarks: — "There are varia- 

 tions of proportion on the parts of the body which 

 may be observed when these fishes are brought to- 

 gether; but the separation of the ventral fins from 

 the anal in Block's Top-Knot, whereas they are 

 closely joined together in the present species, is a 

 more decisive ground of distinction between them." 

 This would unquestionably make our specimens to 

 be Block's Top-Knot. 



Again quoting Couch, " Mr. Thompson of Weymouth 

 has informed me of an exami^le that was orna- 

 mented on the lateral line, near the tail, with a 

 black spot, which had an orange-coloured spot in its 

 centre; and it was also marked with several puce- 

 coloured spots along the base of the dorsal and anal 

 fins." Now, this orange-centred black spot is an in- 

 variable and brilliant characteristic of our Top-Knots, 

 and might with justice call forth the appellation of 

 uniTnaculatus as applied to it by Gunther. " We 

 cannot perceive sufiicient reason for the trivial name 

 given to it by Risso and adopted by Dr. Gunther 

 {uniinaculatus, or one-spotted), since both these 

 species are often, and, it would appear, equally 

 marked by a defined circular spot at the side, which, 

 however, is sometimes not to be perceived." It is 

 not the side spot so frequently noticeable on these 

 fishes that calls forth the name, but apparently this 

 brilliant spot on the lateral line. 



All things considered we are disposed to look upon 

 our species as the variety of Block's Top-Knot 



