Sels. 669 



sufficient respiratory apparatus, a lung-like sac is developed 

 on eacli side of the body behind the head, opening between 

 the hyoid and first branchial arch. The interior of the sac 

 is abundantly provided with blood-vessels, the arterial coming 

 from the branchial arteries, whilst those issuing from it unite 

 to form the aorta. A. cuchia approaches the Eels in having 

 the humeral arch not attached to the skull. 



MoNOPTERUS. — Vent in the posterior half of the body, which 

 is naked. Three branchial arches with rudimentary gills, but 

 without breathing sac. 



One species (if. javanicus), which is extremely common 

 in the East Indian Archipelago and in the eastern parts of 

 the Continent. Upwards of three feet long. 



Symbranchus. — Vent in the posterior half of the body, which 

 is naked. Four branchial arches with well developed gills. 



Three species, of which one (S. marmoratus) is extremely 

 common in tropical America, and the other (S. hengalensis) 

 not less so in the East Indies. 



CHitOBRANCHUS. — Vent in the anterior half of the length of 

 the body, which is naked. Vertical fins reduced to a simple 

 cutaneous fold, without rays. 



A small fish (CA. dorsalis) from North Western Australia 

 and Tasmania. 



Thiety-Fiest Family — Mue^nid^. 



Body elongate, cylindrical or land-shaped, naked or with 

 rudimentary scales. Vent situated at a great distance from 

 the head. Ventral fins none. Vertical fins, if present, confluent, 

 or separated ly the prelecting tip of the tail. Sides of the upper 

 jaw formed hy the tooth-hearing maxillaries, the fore part hy 

 the intermaxillary, which is more or less coalescent with the 

 vomer and ethmoid. Humeral arch not attached to the skull. 

 Stomach with a blind sac ; no pyloric appendages. Organs of 

 reproduction without efferent ducts. 



