ICHTHYOLOGY. 



233 



classifica- 

 tion — Ma- 

 lacopteri. 



Genus IX. Elapsopsis, Kaup. Gapeof the mouth short; snout 

 . elongated, obtuse, stretching beyond the mandible ; the short nasal 

 tube wider at its external orifice than at its commencement ; eye 

 , a})proximating to the corner of the mouth. Pectoral very small but 

 distinctly visible. Body about equal in length to the tail. Nasal 

 teeth reflex, four in each row, with an odd one in front ; vomerine 

 teeth irregularly uniserial ; palatine teeth uniserial anteriorly, be- 

 coming biserial and sub-triserial. One species. 



Genus X. Mystuiopuis, Kaup. Snout spoon-shaped, its ex- 

 tremity being dilated; fore nasal-tube rudimentary, and in the 

 middle of the rostral expansion ; eyes over the middle of the jaws, 

 and though the long head is depressed, they are more lateral than 

 dorsal in their aspect ; gill-openings large and near one another. 

 Two species. 



Genus XI. Mur.enopsis, Lesueur. Head oval; snout not much 

 elongated; hinder nostril rather on the outside of the thin lip. 

 Pectoral as long, or somewhat longer than the long, straight rictus 

 of the jaws. Teeth all of equal length. Three species. 



Genus XII. Echiopsis, Kaup. Face short ; eyes high-placed ; 

 fore nostril-tubes short ; jaws deeply cleft. Pectoral fins pretty 

 short, about half the length of the oral rictus. Nasal teeth seven ; 

 three on the mesial line being the tallest ; two rows of voraerines 

 uniting at their jiosterior termination, biserial palatines, interior 

 row composed of the smallest teeth ; two rows on the mandible, 

 the outer row being the tallest. One species. 



Genus XIII. Scvtalophis, Kaup. Teeth all nearly of a size, 

 divergent; anterior nostril-tube distinctly visible. Pectoral pretty 

 well developed. All the teeth biserial except the nasals. Two 

 species. 



Gp:nus XIV. Leptokhinofhis, Kaup. Snout pointed ; tubes 

 of the anterior nostrils dependant ; posterior nostrils situated be- 

 fore the eyes on the border of the lips ; eyes over the middle of the 

 oral rictus. Pectorals developed'; anal and dorsal fin becoming 

 higher near their terminations. Two sjiecies. 



Genus XV. Pisoodonophis, Kaup. Teeth all shortly conical, 

 more or less blunt ; anterior nostril-tube projecting; eye approxi- 

 mating to the corner of the mouth. Pectoral more or less fully de- 

 veloped. Eighteen species, some of them all of one colour, others 

 spotted or banded. Eighteen species. 



SubOkdee IL— APODALS WITH ARTICULATED FIN 

 KAYS. 



Mater lagoons of the warmer parts of South America, flassifica- 



(jiiiana, Surinam, Cayenne, Demerara, Guyacjuil, Ecuador, '"'° — '^'''" 



lacopteri. 



Fig. iiG. 

 RhamphichtJiys MiilUrL 



The Gtmnotid^ are apodals, but cannot be associated 

 with the Eels in tlie sub-orderof Serpentiform Apodals, owing 

 to the considerable differences of their organization. Tlieir 

 jaws are complete, they are furnished with ribs, and their 

 fin rays are jointed or branched, in which respect they differ 

 from the preceding sub-order, the chief point of agreement 

 being the want of ventral fins. The Gi/mnotidce want also 

 the dorsal ; but one of the genera has a curious long ray, 

 which conmionly lies in a fia-row along the top of the 

 rounded back, glued down by mucus. It is named by 

 German ichthyologists " peitsehe," or " the whip," and is 

 considered by Dr Kaup to be a representative of the adi- 

 pose fin on the tail of the Salmou/'dce. One of the most 

 curious parts of their structure is the forward position of the 

 vent, which in most of the Jihamp/iic/U/ii is before the eye ; 

 and in these the anal begins between the gill plates, and 

 extends along the ventral edge of the fish, l^■hile the roimded 

 back is destitute of a fin. Examples of a similar forward posi- 

 tion of the anus occurs in some other fitmilies, but they are 

 very scarce. Tlic Gi/innotidic inhabit the rivers and fi-esh- 



VOL. XII. 



Fig. W. 

 Sternarchus BonapartiL 



New Granada, and Brazils. The best known species is 

 Gymnolus electriciis, or the Electric Eel. This animal has 

 been well described by Dr Garden of Charlestown, by 

 John Hunter, and by Himiboldt. It is remarkable for the 

 violence of its electric shocks, which are often so powerful 

 as to stupify a man or a horse. The researches of Hunter 

 detected an electric organ in the posterior part of this fish 

 consisting of four longitudinal fasciculi, which occupy one- 

 half the thickness of the part in which they occur, and 

 about one-third of the whole animal. The larger pair lie 

 above, the smaller below. Each fasciculus is composed of 

 flat partitions or septa, with transverse divisions between 

 them. The outer edge of the sejjta appear in nearly ]5arallel 

 lines in the direction of the longitudinal axis of the body, 

 and consist of thin membranes, which are easily torn ; they 

 serve the same purpose as the columns in the analogous 

 organ of the Torpedo, making the walls or abutments for 

 the perpendicular and transverse dissepiments, which are 

 exceedingly ntmterous, and so closely aggregated as to seem 

 almost in contact. The minute jirismatic cells, intercepted 

 between these two sorts of plates, contain a gelatinous mat- 

 ter ; the septa are about one-thirtieth of an inch fi-om each 

 other, and one inch in length contains a series of 240 cells, 

 giving an enormous surface to the electric organs. The 

 whole apparatus is abundantly supplied with nerves fi'om 

 the myelon ; and these nerves are seen coming out in 

 pairs fiom between the vertebra;. In their coiu'se they 

 give out branches to the muscles of the back, and to the 

 skin of the animal. In the Gymnote, as in the Torpedo, the 

 nerves supplying the electric organs are much larger than 

 those bestowed on any part for the purposes of sensation or 

 movement. Hunter thinks, however, that these nerves are 

 more considerable in point of size in the Torpedo than in 

 the Gymnote. These organs are attached loosely to the 

 muscles of the back which lie between the larger fasciculi, 

 and they are immediately connected with the skin by a 

 loose cellular texture. H\imboldt has given a very interest- 

 ing and lively description of the mode of capturing the elec- 

 tric Gymnote, as practised in South America, near the town 

 of Calabozo. 



These fish abound in the stagnant pools of that vicinity. 

 The Indians are well aware of the danger of encountering 

 the Gymnote when its powers are imexhausted. They 

 therefore collect twenty or thirty wild horses, force them 

 into the pools, and when the fish have 'exhausted their 

 electric batteries on the poor horses, they are laid hold of 

 without difficulty. The horses at first exhibit much agita- 

 tion and terror ; they are prevented leaving the pool by an 

 inclosing band of Indians, who goad them with bamboos 

 whenever they attempt to escape. " The Eels," says Hum- 

 boldt, " stimned and confused by the noise of the horses, 

 defended themselves by reiterated discharges of their elec- 

 tric batteries. For some time they seemed likely to gam 



2 G 



