272 PISCES. 



Cephalus, Sh. — Orthagoriscus, Schn. 



Jaws undivided as in Diodon; but the body, compressed and spine- 

 less, is not susceptible of inflation, and the tail is so short and high 

 that this fish resembles one whose posterior portion has been trun- 

 cated, producing a singular appearance, that is amply sufficient to 

 distinguish it. The dorsal and anal, both high and pointed, are 

 united to the caudal; the natatory bladder is wanting; the stomach 

 is small and penetrated directly by the ductus choledocus. A thick 

 layer of a gelatinous substance is spread under the skin. 



C. brevis, Sh.; Tetr. mola, L.; Bl., 128.(1) (The Short Sun 

 Fish.) Four feet and more in length, and weighing upwards of 

 three hundred pounds; the skin is very rough, and of a fine sil- 

 ver colour. European seas. 



C. oblongus; Orthagoriscus oblongus, Bl., Schn., 97. (The 

 Oblong Sun Fish.) Skin hard, and divided into small angular 

 compartments. Cape of Good Hope. 



C. spinosus; Orth. spinosiis, Bl. Schn.; Diodon mola, Pall., 

 Spic. Zool., VIII, pi. iv, f. ; and better, Kaelr., Nov. Com. Pe- 

 trop. X, pi. viii", f. 3. A third and very small species, with a 

 few spines, that is sometimes taken in the Atlantic. 



3d. The flanks only smooth, and with lateral tentacula: T. Spenglen, Bl., 144, 

 Seb., Ill, xxiii, Zand 8, the same as the Tefr. Plumieri, given from Plumier, La- 

 cep., I, XX, o. N.B. That what Lacepede considered a lump is only the pectoral 

 of the other side, the point of which is visible, and that the Sphero'ide tubercul^y 

 Lacep., II, 1, is drawn from the same plate of Plumier, and represents the same 

 fisli seen in front. Schneider was aware of this, Bl., Schn., Ind. pi. vii. — T. hon- 

 kenii, BL, 143. 



4th. Smooth flanks, without lateral tubercles: T. ocellatus, BL, 145; — T. iurgi- 

 dus, Mitch., pL vi, f. 5; — 71 lunaris, Russel, 1, 29. 



II. Species with an oblong- head. 



1st. The flanks only smooth: T. arg-enfa^us, Lacep., Ann. Mus. IV, xiii. 

 2d. Back and flanks smooth, the belly only rough: T. lagocepkalus, Bl., 143» 

 and Seb. Ill, xxiii, 3 and 6; — T. Isevigaius, Will., pi. J. 2. 



III. With a carinated back. T. ro&tratus, BL, 146, 2, to which the T. electricus. 

 Paters. Phil. Trans., vol. 76, pL 3, is closely allied; — T. Gronovii. 



(1) Add Ort. oblongus, Sclin., 97;—Ort. varius, Lacep., I, xxii, 2;—0rL hispi- 

 dus, Nov. Com., Petr., X, viii, 2 and 3. 



N.B. The Ovoidefasc^, Lacep., I, xxiv, 2, the Ovum Commersoni, Schn., 108, was 

 described and figured by Commerson from a stuflfed specimen which he himself 

 suspected was a mutilated Tdraodon, and which, in fact, is a Tetraodon lineatus 

 that had lost its fins. 



The Sphtroide tubercule was given, as we have stated, from a drawing of Plumier, 

 which represents a front view of a Tetraodon whose vertical fins are not visible. 

 Conf , Schn., index, LVII. These two genera must consequently be suppressed- 



