MALACOPTERYGII ABDOM1NALES. 31/ 



less disagreeable than that of the other Siluri. Some American species, with the nead small, rounded, and blunt, 

 having three cirri, and the eyes scarcely perceptible, may form a new subgenus. 



Mytttu, are Siluri with a second or adipose dorsal fin. They are found in the waters of Guiana. 



Pimelodes, body naked, and no lateral armature; but the subgenus requires division and subdivision. First, 

 Jlagrus has small crowded teeth in both jaws and the vomer, and may be subdh ided by the number of cirri, and 

 the shape of the head. With eight cirri, some have the head long and depressed, and others short and broad. 

 With six cirri, some have the snout as depressed, and broader than that of the Pike; Others have the head oval, 

 and a kind of helmet of shagreen-like bones; in others, the head is round and naked; while others, again, ht.ve 

 the head greatly depressed, the eyes low down, and the adipose fin very small ; and there are yet others which 

 have only four cirri. [Some of these, as Pimelodes ct/clopum, are ejected in hot water from volcanoes.] 



Pimelodes, properly so called, want the teeth in the vomer, but often have them in the palate; the cirri and 

 form cit' the bead differ more than in the preceding subgenus; some have but a single row of teeth ; some have the 

 head helmeted, and a distinct bony plate between the helmet and the dorsal spine ; others have a single plate from 

 the snout to the dorsal ; others, again, have the head oval and naked ; some with six cirri, and others eight ; some 

 with a large naked iiead are called Cats, which have six or eight cirri ; then there are others which have the head 

 small and flat, the dorsal minute, and the teeth scarcely perceptible; there are others still which have teeth on the 

 palatals, sometimes like velvet, or like a card, with a buckler on the nape, distinct or united to the helmet, and 

 th« palatal teeth sometimes like a helmet ; some singular ones have teeth like a card, under the skin of the cheek, 

 and moveable; others yet have a lengthened snout, or a pointed one, nearly toothless. These last lead to, — 



Synodontit, with the snout narrow, and the lower jaw supporting an assemblage of teeth laterally flattened, 

 ending in hooks, and individually attached to flexible peduncles. The helmet extends in one plate to the fir:.' 

 spine of the dorsal, which is very strong, as are also those of the pectorals ; the cirri, and sometimes the maxii 

 laries, are barbed. They are found in the Nile and other African rivers, but are not eaten. 



Ageniotus. Some of these have the maxillary turned up in a kind of toothed horn, instead of a fleshy cirrus ; 

 and others have it concealed under the skin, with the dorsal and pectoral spines scarcely visible. 



Doras, have an adipose dorsal, w ith plates in the lateral line, armed with keels or spines; the dorsal and pectoral 

 spines stronglj toothed, the helmet rough, and the shoulder-bone pointed backwards. Some have teeth only in 

 the upper jaw; others have the snout pointed, and the teeth absent, or hardly visible, with occasional lateral 

 bristles to the cirri. 



Heterobranchus, head broad, from the helmet having two lateral pieces of the frontal and parietal bones; oper- 

 culum smaller, but with a tree-like ramification on the third and fourth trill-arch, as a sort of supplemental gills-; 

 viscera like the rest of the family, but they have from eight to fourteen gill-rays, strong pectoral spines, no dorsal 

 one, anil the body long and naked. They inhabit the rivers of Africa, and some of those of Asia. Their flesh is 

 indifferent, or bad. 



One of them, however, Macropteronoles, with a single indented dorsal, constitutes a considerable article of food 

 in Egypt and Syria, where it is called the Sharmuth, or Black Fish. Others have a dorsal with rays, and also an 

 adipose one. Prolosus, have a second dorsal, with rays; and this and the anal long, and uniting to form a tail 

 like an Eel ; lips fleshy ; conical teeth in front of the mouth, globular ones behind, and those above placed on the 

 Vomer; skin naked; nine or ten gill-rays; eighl cirri; and a singular branched appendage behind the vent, be- 

 sides the tubercle common to the family. Some have large and toothed dorsal and ventral .spines; others have 

 them almost concealed under the skin. They are found in the Bast Indies. 



Callichthys, have the sides armed with four rows of scaly plates; head the same, but the snout and under-part 

 of the body naked; one ray in the second dorsal ; pectoral spines strong, and dorsal one feeble; mouth .small; 

 teeth barely visible; four cirri ; eyes small, and lateral. They can crawl out of the water like an Eel. [ These are 

 the subgenera of -i.urus], 



Malapthertmu, has no dorsals with rays, but only a small adipose one in the tail, and no spines in the pectorals. 

 The skin is smooth ; the teeth small and crowded, and are ranged into a broad crescent in each jaw; there are 

 seven gill-rays ; and the jaws and v iscera are like those of Silurua. M. eleetricui, the R a a sc h, or 'l bunder-fish of 

 the Arabs, is the only known Bpecies. It has six cirri, and the head more slender than the body, but enlarged in 

 front. Like the Torpedo and Gymnotas, it can communicate an electric shock, the organ»of which is situated 



between the skin and muscles, and consists Of a cellular tissue, inclosing a fluid, and abundantly fui Dished » ith 



nerves. It is found in the Nile, and the rivers of Central Africa. 



Aspredo, have the head flattened, and the anterior part of the body much widened; the tail long; the eyes small, 

 and placed upwards •, the intermaxillaries under the ethmoid directed backwards, and with teeth on the posterior 



edge only ; and they have the whole gill apparatus immoveable, hem.' soldi led tO the tl QipOl al b mid the pre. 



operculum; gill-opening a mere slit behind the bead, the membrane of five rays adhering e\ irywhere else ; the 

 lower jam is transverse, and shorter than the snout; the first ray of the pectorals is more toothed than in any 



Other of the family ; there is hut one dorsal, « ith a Wl ak Brat ray ; but the anal is long, extending undi 



and slender tail. Some have six cirri, some eighl ; and, in the latter case, one pair are attached to thi 

 the ' thers to the lower jaw In pait i. 



Loricaria, have hard angular plates on the head and body; small intermaxillaxii ■' under 

 the muzzle; transverse disunited mandibles, supporting hooked teeth, which 



flexible. A large membranous veil encircles the opening; the pharynx is furnished with numei 



pavement teeth ; the gill-lids arc Immoveable, bul two small plates supply their i :..ur 



