72 THE VOYAGE OF H.M.S. CHALLENGER. 



Traclujpterus, Gouan. 



A considerable number of species have been described, some of which are without 

 doubt merely stages of growth, while others were described ])y authors who had no 

 opportunity of comparing them with well-authenticated specimens. On the other hand, 

 in a genus which seems to comprise a plurality of species, but in which the distinctive 

 specific characters are obscured by a variety of circumstances, it is difficult to arrive at 

 a satisfactory conclusion with regard to the validity of the species described. One of 

 the most common and best known is the Vagmser or Deal-fish, Trachyptcrus arcticus, 

 from the North Atlantic, of which almost every year one or more specimens are secured 

 on the Norwegian and British coasts after severe gales. From the Mediterranean and 

 neighbouring parts of the Atlantic several species have been described, viz., Trachy- 

 ptenis tmnia (Bl.), of which, according to Emery, Trachyjiterus Jilicauda (Costa), 

 Trachyptcrus iris (Walb.), and Trachyptcrus spinohe (C. and V.), are successive stages 

 of growth ; Trachypterus gryphurus (Lowe) ; Trachyjiterus lioptcmos (C. and V.), 

 Trachyptcrus rUppeUiP (Gthr.) ; Trachypterus cristatus (Bonelli) ; and Trachypterus 

 repandus (Metaxa, Costa). From Cuba a species is described as Trachypterus trachy- 

 uims by Poey, and one from the East Indian Archipelago as Trachypterus scmiophoruK 

 by Bleeker. The instances of the occurrence of this genus in the Pacific are very 

 few, viz., Trachyp>terus altivelis (Kner.), from Valparaiso, Trachypterus weychardti 

 (Philippi), also from the Chilian coasts, and Trachyioterus arawatas (Clarke), from the 

 coast of New Zealand. 



The example in the Challenger collection is only 1^ inches long, and was obtained 

 at Station 207, near the Philippine Islands, when the dredge was used at a depth 

 of 700 fathoms ; but as this extremely delicate specimen was preserved in a 

 tolerably good condition, it is probable that it entered the dredge at no great distance 

 from the surface. It is extremely similar to the small Trachypteriis figured by Costa 

 (Faun, napol., Tab. ix.), under the name of Trachypterus rejyandiis. It has the same 

 shape of body, the same elongate caudal fin, and the anterior dorsal rays and 

 ventral fins are ijrolonged in an extraordinary manner. Also the tail and body are 

 ornamented with transverse dark spots similarly arranged. But the prolonged fin-rays 

 are shorter than in Trachyptenis repandus, and lack lobes of skin. 



It seems to me that both these small individuals represent the young stage of species 

 of Trachyptcrus, which, when older, lose the extraordinary development of their fin- 

 rays. Probably the fish from the Philippine Islands is a species distinct from that 



' The specific ilistinctiicss of this fish has also heeii (loubknl ; ami, tlicriTore, I lioj,' a;;ain to draw attention to the 

 position of the first lateral lilack spot, in which the specimen differs from the other .Mediterranean specimens of the 

 same size which are known to me. 



