ABDOMINAL MALACOPTERYGIANS. 185 



Thus, among those which have but a single band of teeth, some have 

 the head with the helmet, and an osseous plate or distinct buckler between 

 the helmet and spine of the dorsal*. 



In others the buckler is united and forms a single piece with the hel- 

 met, which thus extends from the snout to the dorsal -f. 



In 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 £, 

 and others eight §. 



Some, known under the name of Cats, have a naked but very broad 

 head; one part of these have six cirri |[, and another eighty. 



We should also distinguish those with a small flat head, very small 

 dorsals, and almost imperceptible teeth**. 



Then come those Pimelodes, 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-)")-, or be united with it J J. 

 These palatine teeth are sometimes round, or like small paving-stones §§. 



There are some very singular Pimelodes with teeth, like those of a 

 card, forming a moveable group under the skin of the cheek ||||. 



Others have an elongated snout ^j^|, or one that is even pointed and 

 nearly edentated***. These latter lead to that much more extraordinary 

 group, the 



Synodontis-J -j-f, Cuv. 



Shals, in which the snout is narrow, and the lower jaw supports a bun- 

 dle 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 to the 

 base of the spine of the first dorsal — a spine which is very strong, as are 

 those of the pectorals. The inferior cirri, and sometimes even the max- 

 illaries, have lateral barbs. These fishes are found in the Nile, and in 

 the Senegal: they are not eaten %++• 



* Sil. clariax, Bl. XXXV, i, 2; — Pimel.maculatus, Lacep. V, p. 103; — Sil. hemioli- 

 opterus, BL, Sclin. 



f New species. 



% SUA-maculatus, Bl. 368, 2; — Pirn, namdia, Cuv., Marcgr. 149; — Pirn. Seb<e,C\iv., 

 Seb. Ill, xxix, 5; — Pirn, pirinamp, Spix, 8. 



§ Pirn, octo-cirrhus, Cuv., Seb. Ill, xxix, 1. 



|| New species. 



^f Sil. catus, Lin., Catesb. II, xxiii. 



** New species. 



ft Pirn, herzbergii, Bl. 367? — the Pirn, doigt-de-ndgre, Lacep. 



XX New species. 



§§ New species. 



Illl Pirn, gemidens, Cuv., a new species. 



^1^1 The Karasche (Pirn, biscutalus), Geoff., Eg., Poiss. XIV, i, 2; — Pirn. gagata, 

 Buchan, XXXIX, 65? 



*** Pirn, coniroslris, Cuv. 



■f-ff Synodontis, the antient name of an undetermined fish of the Nile. 



XIX Sil. clarias, Hasselq., very different from the clarias of Gronovius and of Bloch; 

 it is the same as the Si/, schal, Schn., Sonnini, Voy.pl. xxi, f. 2, or as the Pimelode 

 scheilan, Geoff'., Poiss. d'Eg., pi. xiii, f. 3 and 4; — Pimelodus synodontes, Geoff., 11). XII, 

 f. 5; — Pirn, membranacens, Id.. lb., f. 1 and 2. N. B. Schal is their generic appel- 

 lation in lower Egypt — Gurgur in upper Egypt. 



