TELEOSTEI. 23 



TELEOSTEI. 



Synopsis of the Suborders and Families represented in the Nile System. 



I. MALACOPTERYGIL— Air-bladder, if present, communicating with the digestive tract by a 



duct. Opercle well developed. Pectoral arch suspended from the skull ; mesocoracoid 

 arch present. Fins without spines, the ventrals abdominal, if present. Anterior vertebra 

 distinct, without Weberian ossicles. 



A. Supraoccipital separated from the frontals by the parietals. 



1. Prsemaxillary single ; supratemporal very large, plate-like; no free border to the eye ; 



bones of the gill-cover concealed under the skin 1. Mormyrid^e. 



2. Prsemaxillary paired ; maxillary toothed, bordering the mouth. 

 A large hole on each side of the skull ; ribs sessile ; belly with a double 



serrature 2. Notopterid^e. 



No large hole on the side of the skull ; ribs inserted on parapophyses ; 



belly not serrated 3. OsTEOGLOSSlDiE. 



B. Supraoccipital separating the parietals. 



Body scaly ; belly usually serrated 4. Clupeid^e. 



Body naked; mouth very small 5. Cromeriid.e. 



II. OSTARIOPHYS1. — Air-bladder, if well developed, communicating with the digestive tract 



by a duct. Pectoral arch separated from the skull ; mesocoracoid arch present. Fins 

 without spines, or dorsal and pectoral with a single spine formed by the ossification of 

 an articulated ray. The anterior four vertebrae strongly modified, often co-ossified and 

 bearing a chain of small bones (so-called Weberian ossicles) connecting the air-bladder 

 with the ear. 

 Mouth not protractile, usually toothed ; pharyngeal bones normal ; body 



scaly ; an adipose dorsal fin often present . 6. Characinid^e. 



Mouth more or less protractile, toothless ; lower pharyngeal bones large, 



falciform ; no adipose dorsal fin 7. Cyprinid^e. 



Mouth not protractile, usually toothed; pharyngeal bones normal ; body 



naked or wdth bony scutes ; an adipose dorsal fin often present . . 8. Silurid^. 



III. APODES. — Air-bladder, if present, communicating with the digestive tract by a duct. Prge- 

 maxillary bones absent ; the maxillaries, if present, separated on the median line by the 

 coalesced ethmoid and vomer. Pectoral arch, if present, not connected with and remote 

 from the skull ; mesocoracoid arch absent. Fins without spines, the ventrals absent. 

 Anterior vertebrae distinct, without Weberian ossicles. 



Maxillary bones present ; vent far removed from the head ; gill-openings 



separate 9. Anguillim, 



