XXI MALACOPTERYGII 543 
In the classification of Giinther, 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- 
pterygiu ; II. Acanthopterygii Pharyngognathi ; IIT. Anacanthini ; 
IV. Physostomi; V. Lophobranchii; VI. Plectognathi. Group I. 
corresponds to Sub-Order 6 (part), 7 (part), 8 (part), 10 (part) 11 
and 12 of the present work; Group IT. 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." 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. 38. 
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 the 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. 
