MALACOPTEUYGll AliDOMINALES. 217 



and nearly eclentated.(l) These latter lead to that much more ex- 

 traordinary group, the 



Synodontis, Cuv.(2), 



Where the snout is narrow and the lower jaw supports a bundle 

 of teeth, much flattened laterally, terminating in hooks and indivi- 

 dually suspended by a flexible pedicle, a mode of dentation of which 

 there is no other example known. The rough helmet formed by the 

 cranium is uninterruptedly continuous with an osseous plate which 

 extends from the base of the first spine of the dorsal, a spine which 

 is very strong, as are those of the pectorals. The inferior cirri, and 

 sometimes even the maxillaries, have lateral barbs. These fishes 

 are found in the Nile, and in the Senegal: they are not eaten. (3) 



Ageniosus, Lacep. 



All the characters of a Pimelodus, except that there are no true 

 cirri. 



In some, the maxillary bone is turned up into a kind of dentated 

 horn instead of being continued into a fleshy and flexible cirrus. (4) 



In others, it does not project, and remains concealed under the 

 skinj the dorsal and pectoral spines are but slightly apparent.(5) 



Doras, Lacep. 



Machoirans, that is to say Siluri, with a second dorsal, which is 

 adipose, and whose lateral line is mailed with a range of bony plates, 

 each of which is relieved by a spine or salient carina. The dorsal 

 and pectoral spines are very strong and deeply dentated; the helmet 



(1) Pirn, conirostris, Cuv. 



(2) Synodontis, the ancient name of an undetermined fish of the Nile. 



(3) Sil. clarias, Hasselq., very different from the clarias of Gronovius and of 

 Bloch; it is the same as the Sil. schal, Schn., Sonnini, pi. xxi, f. 2, or as the Fime- 

 lode scheilan, Geoff., Poiss. d'Eg., pi. xiii, f. 3 and 4; Pimelodus synodontes 

 Geoff., lb., XII, f. 5; Pirn, membranaeeus. Id., lb., f. 1 and 2, N.B. Schal is 

 their generic appellation in lower BgyptGurgur in upper Egypt. 



(4) Silurus militaris, Bl., 362. 



(5) Sil. inermis, Bl., 363, Seb. Ill, xxix, 8;Pimel. silondia, Buchan., VII, 50. 

 N.B. The Silurus ascita, lu.. Ad. Fred. pi. xxx, f. 2, is nothing else than a 



common Pimelodus quitting the egg, the yelk of which has not yet completely 

 entered the abdomen. Linnsus took this yelk for an ovary, and Bloch has para- 

 phrased his mistake. It was also through an error of the press that Linnxus is 

 made to place four cirri on the upper jaw his figures exhibit them on the lower 

 one. 



Vol. II. 2 C 



