28 MOEMYEID^. 



been more fortunate, and the Mormyrs have proved a great success in the Gezira 

 aquarium, examples of three species, belonging to the genera Marcusenius, Gnatho- 

 nemus, and Mormyrus, having lived from ten to twenty-six months *. The species with 

 comparatively large mouths (Mormyrops, Gymnarchus) feed principally on fishes and 

 crustaceans, the others on tiny animals and vegetable and more or less decomposed 

 matter. Delhez, on the Congo, found that many are attracted to the borders of the 

 river in the neighbourhood of human dwellings, where they feed on the refuse thrown 

 into the water. It is probable that the species with a rostrum use it to procure small 

 prey hidden between stones or buried in the mud, and that the fleshy mental appendage 

 with which many are provided is a tactile organ compensating the imperfection of 

 the vision in the search for food. Until quite recently, absolutely nothing was known 

 of the breeding-habits and development. To the late J. S. Budgett we owe some very 

 interesting observations made in the Gambia on Gymnarchus niloticus. 



Venerated by the ancient Egyptians, the Mormyrs are frequently represented on 

 hieroglyphics and mural paintings as well as in bronze models. The " Oxyrhynchus " 

 {Mormyrus kannume and M. caschive) are the most frequently depicted ; but repre- 

 sentations of the " Bana " (Petrocephalus bane) and of GnatJionemus cyprinoides and 

 Mormyrus hasselquistii also occur, the best being in the great fishing-scenes painted 

 on the walls of the tombs at Giza and Sapara f . There is also a very recognizable 

 painting of the " Bana " in the Tomb of Ti, Sakkara, as I find from an unpublished 

 photograph in Prof. Flinders Petrie's collection. 



Synopsis of the Genera. 



I. Mormyrik^e. — Ventral, anal, and caudal fins present ; teeth on the paraspbenoid and on the 

 tongue ; vertebrae 37 to 64 ; peculiar (Gemmingerian) linear bones, along each side of the 

 tail, above and beneath the electric organ (cf. PI. VII. fig. 3) ; scapular foramen in 

 the scapula, or between the scapula and the coracoid ; air-bladder simple. 

 A. Anal fin two-thirds to once and three-fourths the length of the dorsal, with more than 

 20 rays. 

 Mouth terminal or subinferior, with 10 or more teeth in each jaw ; 



nostrils remote from the eye 1. Mormyrops, J. Mull. 



Mouth inferior, with 10 or more teeth in the upper jaw and 18 or more 



in the lower ; nostrils close together and close to the eye ... 2. Petrocephalus, Marcus. 

 Mouth inferior or subinferior, with 3 to 9 teeth in the upper jaw and 



4 to 10 in the lower ; nostrils widely separated from each other . 3. Marcusenius, Gill. 

 Mouth terminal ; 3 to 10 teeth in the upper jaw, 4 to 10 in the lower ; 



nostrils widely separated from each other 4. GnatJionemus, Gill. 



* Cf. Flower, 5th and 6th Ann. Eep. Zool. Gard. Giza (Cairo, 1904, 1905J, pp. 39, 24, and Guide Gezira 

 Aquarium (Cairo, 1904), p. 3. 



t Cf. Lepsius, Denkmaeler, Abth. ii. (Pyramids of Giza, pi. ix., and Pyramids of Sapara, pi. xlvi.). 



