THE ORDERS OF TELEOSTOMOUS FISHES 467 



Superorder Malacopteroidei nom nov. 1 

 Physostomi 2 (/. Muller in part.) 



(ISOSPONDYLI + OSTARIOPHYSI.) 



(Plate XXIX.) 



The connection between the Ostariophysi or Characin-Carp- 

 Catfish series and the Isospondyli or typical soft-rayed fishes 

 (e. g. Clupeidae, Salmonidae, Osteoglossidae) is indicated by the 

 following characters in common: 



(i) The air bladder if well developed communicates with the 

 digestive tract by a duct. (2) The mesocoracoid arch is present. 

 (3) The orbitosphenoid is present. (4) The pelvic fins 

 if present are abdominal. (5) The fin rays (except the single 

 pectoral and dorsal spines of Catfishes) are soft or articulated. 

 (6) The presence of an adipose dorsal fin in many Heterognathi 

 (Characins) and Nematognathi (Siluroids) as in the Salmon-like 

 fishes. However all these common characters may have been 

 inherited from different ancestral families of the Mesoganoidei 

 (p. 465). Boulenger restricts the term Malacopterygii of Artedi 

 and of Cuvier to practically the same content as the term Iso- 

 spondyli of Cope, the two divisions, Malacopterygii and Ostario- 

 physi, being given coordinate rank as suborders of the order 

 Teleostei. For the reasons given it seems better to use a new 

 term, Malacopteroidei, in abroad or superordinal sense to include 

 the two orders Isospondyli Cope and Ostariophysi Sagemehl. 



Order Isospondyli 3 Cope 



The name Isospondyli refers to the fact that, in contrast with 

 the Ostariophysi (see page 472), the anterior vertebrae are not 

 coalesced, nor are their processes modified into Weberian auditory 

 ossicles. The vertebral centra are calcified, without separate 

 pleuro- and hypocentra, but sometimes (in the Leptolepididae) 

 slightly perforated by the notochord. The broad maxillary 

 forms part of the margin of the upper jaw, in the more primitive 



1 fxaXaxoi, soft, itzepov, fin. 



2 q>v6oi, bladder, 6z6fxa , mouth, in allusion to the duct from the swim 

 bladder into the oesophagus. 



» 160S, equal, 6novdvXoi, vertebra. 



