M ALACOPTERYGII 543 



In the classification of Glinther, which has been generally in 

 use in this country for the last thirty years, the Teleosts were 

 divided into six principal groups, of ordinal rank : I. Acantho- 

 pterygii ; II. Acaiithopterygii Pharyngognathi ; III. Anacanthini : 

 IV. Physostomi ; V. Lophobranchii ; YI. Plectognathi. Group I. 

 corresponds to Sub-Order 6 (part), 7 (part), 8 (part), 1 (part) 1 1 

 and 12 of the present work; Group II. to Sub-Order 10 (part); 

 Group III. to Sub-Order 9 and 10 (part); Group IV. to Sub- 

 Order 1, 2, 3, 4, 5, 6 (part), and 8 (part) ; Group V. to Sub- 

 Order 7 (part); and Group VI. to Sub-Order 13. 



Sub- Order 1. Malacopterygii. 



Air-bladder, if present, communicating with the digestive tract 

 by a duct. Opercle well developed. Pectoral arch suspended 

 from the skull ; mesocoracoid arch present. 1 Fins without spines, 

 the ventrals abdominal, if present. Anterior vertebrae distinct, 

 without Weberian ossicles. 



This sub-order, which corresponds to the Isospondyli and 

 Scyphophori of Cope and to a part of the Isospondyli of A. S. 

 Woodward, embraces the most generalised of the Teleosts, and is 

 intimately connected with the Ganoids by the fossil forms which 

 are placed at the base of the series of families. The physosto- 

 mous condition of the air-bladder, the connexion of the pectoral 

 arch with the skull, the presence of the mesocoracoid arch, the 

 backward position of the many-rayed ventral fins, the normal 

 condition of the anterior vertebrae, the absence of true spines 

 to the fins, and the separation of the supraoccipital bone from the 

 frontals by the parietals, are primitive characters which among 

 the Teleosts occur combined in some families of this sub-order 

 only. The mesocoracoid arch is retained by the Ostariophysi, 

 which differ in the remarkably modified condition of the anterior 

 vertebrae, but it disappears in all other Teleosts, which gradually 

 acquire a more forward position of t'he ventral fins and a reduc- 

 tion in the number of their rays, develop spines in the vertical 

 fins, and lose the communication of the air-bladder with the 

 outside. 



The Malacopterygii may be divided into twenty-one families, the 

 characters of which are contrasted in -the following synopsis : 



1 See p. 553, Fig. 333, B. 



