636 TELEOSTEI CHAP. 
Five or six species, referable to two genera, Pegasus and 
Parapegasus, make up this family. They are very small fishes, 
inhabiting the coasts of China, Japan, Arabia, the Malay Archi- 
pelago, and Australia. Pegasus is remarkable among all fishes 
in having the five anterior rays of the pectoral fin transformed 
into strong spines. 
Sub-Order 8. Percesoces. 
Air-bladder, if present, without open duct. Parietal bones 
separated by the supraoccipital. Pectoral arch suspended from 
the skull; no mesocoracoid arch. Ventral fins, if present, abdo- 
minal, or at least with the pelvic bones not solidly attached to 
the clavicular arch. 
This group connects the Haplomi with the Acanthopterygii, 
the Scombresocidae being somewhat related to the Cyprinodonts,! 
whilst the Anabantidae show distinct affinity to the Osphro- 
menidae in the following sub-order. Other families, previously 
included among the Scombriform Acanthopterygians, are placed 
here on the assumption that the loose attachment of the pelvic 
bones to the clavicles is a primitive character, and not the result 
of degeneration, such as occurs in some cases among true Acan- 
thopterygians. Although this sub-order is perhaps only ai 
artificial association, it must be borne in mind that, notwith- 
standing the very wide divergence which exists between the first 
and last families, and however dissimilar their members may 
appear to be at. first sight, a gradual passage may be traced con- 
necting the most aberrant types. 
SYNOPSIS OF THE FAMILIES. 
I. Ventral fins, if present, inserted far behind the pectorals; no spines to 
the fins. 
Ribs attached to the extremity of much-developed parapophyses; lower 
pharyngeal bones completely united ; pectoral fins inserted very high up 
1. Scombresocidae. 
1 Swinnerton (Quart. J. Micr. Sci. xlv. 1902, p. 554) has pointed out that the 
skull of the Scombresoces belongs to what he terms the Acrartete type (¢.e. in 
which the attachment of the palatine cartilage or its derivates is confined to the 
pre-ethmoid cornua), whilst the other Percesoces examined by him, as well as the 
Cyprinodonts are Disartete (the attachment being at the parethmoid and _pre- 
ethmoid cornua); but the character is so indistinctly defined in some adult 
Cyprinodonts -that I feel some diffidence in making use of this character for 
systematic purposes in the present state of our knowledge. 
