PLECTOGNATHES. 233 



I separate from the genera of Diodons and Tetraodons, 



Cephalus, Sh. — Orthagoriscus, Schn., 



The Moles, vulgarly called Sun Fishes, which have the jaws undi- 

 vided as in Diodon ; but the body, compressed and spineless, is not 

 susceptible of inflation, and the tail is so short and high that this fish 

 resembles one whose posterior portion has been truncated, producing a 

 singular appearance, which is amply sufficient to distinguish it. The 

 dorsal and anal, both high and pointed, are united to the caudal ; the na- 

 tatory 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. mold, L. ; Bl. 128*. (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 silver 

 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. spinosus, Bl. Schn.; Diodon molct, Pall., 

 Spic. Zoo). VIII, pi. iv, f. ; and better, Kaelr., Nov. Com. Petrop. 

 X, pi. viii, f. 3. A third and very small species, with a few spines, 

 which is sometimes taken in the Atlantic. 



D. With pale spots; — Tetr. testudineus, Bl. 139, of which the T. reticularis, Bl., 

 Schu., appears to be a variety ; — T. hispidus, Lacep. I, xxiv, 2, and Geoff. Poiss. d'Eg. 

 I, 2;—T. patoca, Buchan. XVIII, 2. 



2nd. The entire body smooth: T. kevissimus, BL, Schu. ; — T. cuiculia, Buchan. 

 XIII, 3. 



3rd. The flanks only smooth, aud with lateral tentacula: T. Spengleri, Bl. 14<t, 

 Seb. Ill, xxiii, 7 and 8, the same as the Tetr. Plumieri, given from Plumier, Lacep. 

 I, xx, 3. N. B. That which Lacepede considered a lump is only the pectoral of the 

 other side, the point of which is visible, and that the Sphero'ide tubercule, Lacep. II, 

 1, is drawn from the same plate of Plumier, and represents the same fish seen in 

 front. Schneider was aware of this, Bl., Schn., Ind. pi. vii; — T. honkenii, Bl. 143. 



4th. Smooth flanks, without lateral tubercles: T. ocellatus, Bl. 145; — T. turgidus, 

 Mitch, pi. vi, f. 5; — T. lunaris, Russel, I, 29. 



II. Species with an oblong head. 



1st. The flanks only smooth: T. argentatus, Lacep., Ann. Mus. IV, xiii. 

 2nd. Back and flanks smooth, the belly only rough: T. lagocepltalus, Bl. 143, and 

 Seb. Ill, xxiii, 5 and 6; — -T. loevigatus, Will., pi. J, 2. 



III. With a carinated back: T. rostralus, Bl. 140, 2, to which the T. eleclricw, 

 Paters. Phil. Trans, vol. 76, pi. 3, is closely allied; — T. Granovii. 



* Add, Ort. oblongus, Schn. 97; — Ort. vurius, Lacep. I, xxii, 2; — Ort. hispidus, 

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



N.B. The Ouo'ide faxce, Lacep. I, xxiv, 2, the Ovum Commersonii, Schn. 108, was 

 described and figured by Commerson from a stuffed specimen which he himself sus- 

 pected was a mutilated Tetraodon, and which, in fact, is a Tetraodon limatus that had 

 lost its fins. 



The Sphero'ide tubercule was given, as we have stated, from a drawing of Plumier, 

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

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



