358 



SCANDINAVIAN FISHES. 



Exocoetus voUtans, Lin., Syst. Nat., ed. XII, toin. I, p. 520 



(ex. Gron. Zooph.); Cuv., Val., Hist. Nat. Poiss., vol. XIX, 



p. 83, tab. 569; Steind., Stzber. Akad. Wiss. Wien, Math. 



Nsturw. CI., LVII, I, 1868, p. 734; Ltkn, Vid. Meddel. 



Xaturh. For. Kbhvn 1876, pp. 393 et 401; Moii., Hist Nat. 



Poiss. Fi:, torn. Ill, p. 481; Day, Fisli. Gt. Brit.. Irel, 



vol. II, p. 154, tab. CXXVIII. 

 Exocoetus e.vilicns, Bl., Natiirg. Ausl. Fiscli., part. IX, p. 10^ 



fab. CCCXCVII; Cuv., Eegn. Anim., ed. 2, torn. II, p. 287; 



SwAKs.. Nat. Hist. Fish., Ampli., Rept., vol. II, p. 296; 



Couch, Fish. Brit. IsL, vol. IV, p. 128, tab. CCYII; Lii.lj. 



(exsiliens), «i'u., Norg. Fn., Fisk., vol. II, p. 460. 

 Exocoetus {volitansr). Coll., Forh. Vid. Selsk. Christ. 1874, 



Tillaagsli., p. 177; Exoc. sp. n. '?, Ltkn, I. c, p. 403; 



Coll., Forh., 1. c., 1879, No. 1, p. 95; Malh, Ghgs, Boh. 



Fn., p. 555. 



Obs. Tlic iirst to distiuguisli between more than one species of 

 Flying-fish Avithin tliis family was Gronovius, and the firsi to give 

 systematic names to the two species which this author had esfablished, 

 was LiNN.'EUS, who had previously united them both umk-r the name 

 of volitans. LiNNiEUS made the mistake, in the twelfth edition of 

 Sijstema Natunr, of allowing his original description (in Balk's thesis: 

 Mus. Ad. Frid., p. 42 and in Amoen. Acad., vol. I (1749), p. 320) 

 of Exocoetus {Halocypsehis) evolans with shorter ventral fins (o be in- 

 cluded in the list of synonyms of Exocoetus volitans instead of Exo- 

 coetus evolans, to which species according to Lilljeborg wo should 

 refer the type-specimen in Upsala Museum. However, this cannot 

 give rise to any ambiguity, for it is evident that Linn.eus grounded 

 his opinion chiefly on the distinction drawn by Gronovius. It is less 

 advisable t<i follow Bi.ucH, and adopt for Exocoetus volitans the spe- 

 cific name of exsiliens from Linn^IUs's Mantissa Plantarum 1771, p. 

 529, for in this passage Linn.eus describes a young Flying-fish, as 

 yet of doubtful species, "with the 1st and 2nd rays of the pectoral 

 fins short," a character which, up to the present at least, we have no 

 right to regard as evanescent and belonging to young specimens. With 

 respect to the limitation of the species, it is evident from the above 

 diagnosis and fin-formula that we regard it as identically the same as 

 Valenciennes' Exocoetus lineatus (Cuv., Val., Hist. N'at. Poiss., XIX, 

 p. 92), the chief distinction between which and Exoc. volitans is said 

 to lie in the somewhat greater number of rays in the anal fin (10 

 according to Valenciennes; 10 or 11 according to GOnther, Oat., p. 

 287). LtiTKEN has shown that the white transverse band on the pec- 

 toral fins may also occur in Exoc. volitans. Whether this species is 

 distinct from Ranzanis' Exoc. bnhiensis (see Bleekek: Atl. Ichth. Ind. 

 Or. Neerl., tome VI, p. 71, tab. CCXLIX, fig. 2), is a question that 

 must be settled by a more minute investigation of the point whether 

 Exoc. volitans is alwa3's without the small teeth on the palatine bo- 

 nes, and whether they are constant in Exoc. bahiensis. 



The Great Flying-tish may well be regarded as the 

 most pronounced example of tho.se singular habits which 

 have given the genus its name. It is no better known 



than its kindred species; but it is probably the com- 

 monest, at least in the Atlantic — and perhaps in the 

 Mediterranean, where however, according to Giglioli", 

 Exocoetus Bondeletii, a near relation, is commoner. Most 

 of the observations of Flying-fishes the species of which 

 has not been fixed, prol)ably refer either to this species or 

 to Halocypselus evolans, also a common species. In size 

 too, it stands first: the Royal Museum possesses speci- 

 mens taken near St. Helena, Avhich measure between 

 about 48 and 55 cm. in length to the end of the 

 inferior lobe of the caudal fin. 



Much has been written of tlie fliiiht of the Fhine- 

 fish; and we have ascertained, chiefly from Mobius'', 

 that it is quite different from the flight of birds or 

 insects or the fluttering of a bat, and more closely re- 

 sembles the leaping movements made through tlie air 

 by the Flying Squirrels or the Flying Lizards (Dragons). 

 By the help of the large and strong lateral muscles of 

 the body the fish attains the speed of an arrow, which 

 it maintains above the Avater, slackening, of course, 

 towards the end, and thus traverses a distance of from 

 100 to 150 metres through tlie air in less than 20 se- 

 conds'. At the same instant as it leaves the surface 

 of the water, the pectoral and ventral fins are expanded. 

 It supports itself principally on the former fins, l^ut 

 almost passively, the wind and the pressure of the at- 

 mosphere bearing the flsh along without au}' exertion 

 on its own part, save that needed to keep these fins 

 expanded. There is no independent motion of these 

 fins, according to Mobius; but when the wind blows in 

 a direction exactly parallel to their plane, the hind 

 margin flutters, like the sails of a boat in stays. The 

 Flying-fish cannot steer an independent course'', accord- 

 ing to Mobius, the direction of its flight being fixed 

 by the impetus once gained; and when the speed slack- 

 ens, we may see its course changed by the wind, when 

 the latter is not dead ahead, for some seconds before 

 the fish falls back into the waves. According to Mo- 

 bius the fish is hardly able to rise or descend at will, 

 and when it is seen moving up and down along the 



« Espoz. Intern., I'esca, Berlino 1880, Sez. Ital., Catal., p. 103. 



' Zeitschr. f. Wiss. Zool., 30 Bd, Suppl., (1878), p. 343. 



' According to Moiiius the flight seldom lasts longer than 10 or 15 seconds. 



'' Each ray in the pectoral fins, with the exception of the first two, in the case of which the sinew of the ostensory muscles is coin- 

 uion, is furnished, as is well known, with a distinct double pair of muscles. L. Agassiz, who during his voyage to Brazil in 1865, devoted 

 particular attention to the habits of the Flying-fishes in the Atlantic (see A Journey in Brazil, p. 522), denies that the Flying-fish is en- 

 tirely destitute of the power of altering the plane of the expanded fins by means of these muscles and thus rising or falling during its flight, 

 or that it is ipiife unable to change the direction of its course by bending its body. Even MObius acknowledges that it often happens that 

 Flying-fish w'hich are just above the surface, alter their course by means of the inferior lobe of fhe caudal fin, which then hangs down in 

 the water. 



