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Show 216 I)ISCES. PIMELODUS, pt•operly SO called. The band of teeth in the vomer parallel to t?at in the upper jaw is wanting, but teeth are frequently observed m the palate. The true Pimelodi, as to the number of filaments and form of the head, present a greater variety than the Bagri. . Thus among those which have but a smgle band of teeth, some have the head helmed, and an osseous plate or distinct buckler between the helmet and spine of the dorsal.( 1) In others, the buckler is united and forms a single piece with the helmet, which thus extends from the snout to the dorsal.(~) Jn others again the head is oval, and covered with skin only, through which the bones are not perceptible; of this group some have six cirri,(3) and others eight.( 4) Some, called Cats, have a naked but very broad head; one part of these have six cirri,(5) and another eight.(6) We should also distinguish those with a small fiat head, very small dorsals and almost imperceptible teeth.(7) Then come those Pimelodi, which, besides the band of teeth in the jaw, have plates of them in the palatines; these latter teeth may be either small and crowded, or bent like those of a card, and then the plate on the nape may be either distinct from the helmet,(S) or be united with it.(9) These palatine teeth are sometimes round, or like small paving-stones.( 10) There are some very singular Pimelodi with teeth, like those of a card, forming a movable group under the skin of the cheek.(!!) Others have an elongated snout,(12) or one that is even pointed (1) Sil. clarias, Bl. XXXV, i, 2;-Pimel. maculatus, Lacep., V, p. 103;-Si/. hemioliopterus, Bl., Schn. (2) New species. (3) Sil. 4-maculatus, Bl., 368, 2;-Pim. namdia, Cuv., Marcgr., 149;-Pim. Sebre, Cuv., Seb. III, xxix, 5;-Pim.pirinamp., Spix, 8. (4) Pim. octo-cirrltus, Cuv., Seb. IH, xxix, 1. (5) New species. (6) Sil. catus,Lin., Catesb., II, xxiii. (7) New species. (8) Pim. herzbergii, BJ., 367?-the Pim. doigt-de-negre, Lacep. (9) New species. (10) New species. • ( 11) Pim. f{emidens, Cuv., a new species. (12) The Karcuche (Pim. biscutattts), Geoff., Eg., Poiss, XlV, i, 2;~Pim.gagata, Buchan., XXXIX, 65? MALACOPTERYGII AIHJOMINALES. 217 and nearly edentated.( 1) These latter lead to that much more extraordinary 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 individually 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 &kin; the dorsal and pectoral spines are but slightly apparent.( s) DonAs, 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) Pim. 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, pl. xxi, f. 2, or as the Pimelode scheilan, Geoff., Poiss. d'Eg., pl. xiii, f. 3 and 4;-Pimelodua synodontea Geoff., lb., XII, f. 5;-Pim. membranaceus, Id., lb., f. 1 and 2. N.ll. Schal is their generic appellation in lower Egypt-Gurgur in upper Egypt. (4) Silurua militaris, Bl., 362. (5) Sil. inermis, Bl., 363, Seb. III, xxi:x:, 8;-Pimel. silondia, Buchan., VII, 50. N.B. The Silurus ascita, ,L., Ad. Fred. pl. :x::x:x, f. 2, is nothing else than a common Pimelodus quitting the egg, the yelk of which has not yet completely entered the abdomen. Linna:us took this yelk for an ovary, and Bloch has paraphrased his mistake. It was also through an error of the press that Linna:us is made to place four·cirri on the upper jaw-his figures exhibit them on the lower one. VoL. II.-2 C \ |