SCoMIiRilIDS. 



103 



THE PLAIN PELAMIS. 

 ORGYNOPSIS IJMCOLOK. 



Fig. 29. 



Back dark sfecl-hiae. Belly silrenj. No distinct stiijies or bands in the colotirinf/ of the bodij (in adult speci- 

 mens). Mandible about as long as the base of the anal fin or the length of the pectoral, or even a little shorter 



than the latter. 



,^' 



:^"X, 



Fig. 29. Plain Pelamis {Orcynopi^is iinicolor), from PioluiKlsin. ^^ ijutiiral size. 



R. hr. 7; /). 13' , " ,„ VIII; .4 



11 1. 12 



11 1. 12 



VII: P. 2 



. + 21: 



V. ','5; C. x+\~iJt.v. 



l>'ijn. Scomber unicolov, Geoffr., Descr. de I'Egypte, Poiss., tab. 24, 

 fig. 6(?); Gthr {Pelaiivjs), Cat. Brit. Miis., Fish., vol. II, 

 p. 368; Gill (Orcynopsis), Proc. Acad. Nat. Sc, Philad., 

 1862, pp. 125 et 126; CedebstrSm (Felamys) Ofvers. Vet.- 

 Akad. Forh. 1876, No. 4, p. 64; SundsteOm, Fn. iSverg. 

 Ryijgr., p. 227; Coll, (Orcynopsis), Vid. Selsk. Forli. Christ. 

 1879, No. 15, p. 3; Gigl. {PelamicJithys), Espos. Int. Peso. 

 Berl. 1880, Cat. Sez. Hal., p. 85; Lillj., (Orcynopsif), 

 Sv., Norg. Fisk., vol. I, p. 266. 



Cybium Boiiaparti, Yer., Att. 8:va Riun. Scienz. Ital. Genov. 

 1846, p. 493; Fil. et Vek. (Pelamy.''), Mem. R. Accad. Sc. 

 Tor., ser. 2, torn XVIIl, p. 194, tab. fig. 4; Mor., Hist. 

 Nat. Poiss. Fr., vol. II, p. 434. 



Tliyniius pereyriniis, Coll., Vid. Selsk. Foih. Christ. 1879, 

 No. 1, p. 20, tab. 1, fig. 1. 



Obs. Whether ROppel's Thynnus (Pelamis) imicolor" is iden- 

 tical with this species, as LOtken* thought probable, cannot yet be 

 decided. The difference in colour — the glossy, reddish violet of the 

 belly, and the white tips of the second dorsal and the an:il fins in 

 RtlrPELL's form — as well as the difference in the fin formula — one 

 ray more or less in the first dorsal — is certainly unimportant 

 when we consider the similarity in other respects. But the compa- 

 ratively long ventral tins and the low anterior dorsal in RCrrELLS 

 figure would form more important distinctions, if one could rely on 



these points when there is no mention of tiieni in the description, 

 and when they are possibly differences of sex or age. The great 

 difference which we see in Rvppell's figure between the length of 

 the lower jaw and the base of the anal fin, which is considerably 

 shorter, is also worthy of notice. 



The Plain Pelamis, which attains a length of about 

 8 dm., is fairly elongated in form, like the following 

 species, but more compressed than the true Tunny. 

 The character, too, which is expressed in the small 

 extent of the corslet, is conunon to both the species 

 of Pelamis; but in the Plain Pelamis a belt of scales, 

 starting from the corslet, runs along the whole of the 

 lateral line, which is more even and less undulating 

 in its course than in the Striped Pehimis. In compa- 

 rison with the latter the hind part of the body is more 

 elongated, the beginning of the second dorsal fin being 

 situated in front of the middle of the body. The 

 corslet is less marked than in the Tumiy, but simihir 

 in form, with clearly defined sinuses at the beginning 

 of the lateral line. The u])permost sinus extends for- 

 ward Mlong the side of the back to the gill-opening, and 

 al)Ove it the scaly covering of the body follows the bases 

 of l)oth dorsal fins; the second sinus extends forward 



" Xeue Wirbellh., IV, (Fische d. Eothen Meercs), p. 40, tab. 12, fig. 1 = Pelamys mida, Gthr, Cat., 1. c; Kluxz., Verb. Zcol. 

 Bot. Ges. Wien, 21 (1871), p. 443. 

 ' Spot. Atl., 1. c, p. 477. 



