214 SUB-CLASS (AND ORDER) TELEOSTEI. 



the base of the dorsal and anal (if present) fins. f. w. of tropical 

 Afr. They possess an electric organ on each side of the tail with feeble 

 electric functions, consisting of modified muscle- tissue. The snout fre- 

 quently of strange shape ; eyes often reduced. The brain is remarkable 

 for its size ; 10 genera. Mormyrus L., teeth in rows along 

 the middle of the palate and the tongue ; M. oxyrhynchus Geoff., venerated 

 by the ancient Egyptians ; Hyperopisus, Mormyrops ; Gymnarchus Cuv., 

 Nile and W. Afr. rivers, eel-like, each jaw with incisor-like teeth ; 

 air-bladder cellular, very extensible, duct with sphincter at oesophageal 

 opening ; lays very large eggs ; the gills of the embryo project beyond 

 the gill-openings. Gnathonemus. 



Fam. 3. Clupeidae. Body covered with scales, head naked ; supra- 

 occipital in contact with frontal. Abdomen frequently compressed into 

 a serrated edge. Maxillaries (of three pieces) and premaxillaries both 

 enter into upper jaw. Opercular apparatus complete. Adipose fin 

 absent, dorsal not elongate, anal sometimes very long. Stomach with 

 blind sac, pyloric caeca numerous. Gill openings usually wide. Pseudo- 

 branch usually present. Air-bladder simple, large, communicating with 

 the ear. Principally coast fishes ; none from the deep sea ; may enter 

 f. ws. communicating with sea ; temp, and trop. zones. Many 

 fossil forms. Engraulis C. et V., anchovies, upper jaw prominent ; 

 mouth with a very deep cleft ; eyes covered by skin ; E. encrasicholus L. 

 (Anchovia J. and E.), the anchovy, abundant in Med., also 

 taken in E. Channel ; Cetengraulis Gthr. ; Stolephorus Lac. ; Coilia 

 Gray ; Dussumieria ; Etrumeus ; Chatoessus C. et V. (Dorosoma Raf.% 

 C. Amer., Aust., E. Ind., Japan. Clupea Cuv., herrings, upper 

 jaw not projecting, eyes with free lateral adipose lids, more than 

 60 species, most used as food, but some trop. species poisonous ; 

 C. harengus L., the herring, incredibly prolific, whitebait consists 

 chiefly of the young of the herring (and sprat), the air-bladder opens 

 into the stomach, and also on the left side near the anus,* the eggs are 

 attached to stones, etc.; C. pilchardus Walb. (Clupanodon Lac.), the 

 pilchard (the young is the sardine), equally abundant in Brit. Channel, 

 on coast off Portugal and in Med. ; C. sprattus L., the sprat, 

 in Norfolk sold as anchovies ; C. alosa L. (Alausa, Alosa), the shad or 

 allice-shad, coasts of Eur. ascending rivers ; C. finta, the twaite-shad. 

 Other Clupeoid genera are Clupeoides, Pellonula, Clupeichthys, Pellona, 

 (Ilisha), Pristigaster, Chirocentrodon, Pomolobus, Sardinella, Opisthonema, 

 Brevoortia, Opisthopterus, Odontognathus, Pristigaster ; Chanos Lacep. 

 wih accessory branchial organf in a cavity behind the gill-cavity, Indo- 

 Pac., 4 ft., edible. 



The following genera may be placed here : Elops, Megalops (M. atlan- 

 ticus, the tarpon), Albula (Butirinus) with a trace of the conus (with two 

 rows of valves) in the heart ; Pterothrissus (Bathythrissa), deep sea, Japan. 



Fam. 3a. Hyodontidae (moon eyes), f. w. fish of N. America, 

 no oviducts ; Hiodon, Le Su. 



Fam. 4. ' Alepocephalidae. Deep-sea fishes approaching the Sal- 

 manoids ; without adipose fin or air-bladder. Phosphorescent spots 

 none or small. Stomach curved, without blind sac ; pyloric caeca in 

 moderate number. Pseudobranch present. Alepocephalus, Mitchillina, 

 Bathytroctes, Talismania, Conocara, Platytroctes, Aleposomus. 



* Weber, " De aure et auditu," 1, 1820, vii., 63. 

 f J. Miiller, Bau u. Grenzen d. Ganoiden, p. 75. 



