45 6 
TUBE-BLADDERED GROUP. 
In the armoured cat-fish, forming the genus Loricaria, the body is remarkable for 
its elongated and slender form; while the head is depressed, with a more or less 
produced and spatulate snout, on the under surface of which the mouth is situated 
at a considerable distance from the extremity, its margins being surrounded by 
large folds, and each corner having a barbel. Both the dorsal and anal fins are 
short and elevated, and the entire head and body enveloped in a bony cuirass. 
SECTION PLECTISPONDYLI. 
The Carp Tribe, —Family Cyprinidm. 
Adopting a modification of Professor Cope’s classification, the eels and their 
allies may bo regarded as forming one sectional group of the suborder, while the 
cat-fishes constitute a second by themselves. A third equivalent group will then 
be made by the carps, together with the under-mentioned family of the characinoids 
and certain allied forms. This third group—for which the name Plectispondyli has 
been proposed—while agreeing with the cat-fishes (forming the group Nematognathi) 
in having the first four vertebrae fused together and highly modified, differs in the 
presence of a subopercular bone. As in the last family, the margin of the upper 
jaw is formed by the premaxillae, and the whole mouth is toothless, teeth being 
developed on the pharyngeal bones alone. While the head is invariably naked, the 
body is generally covered with scales, and although it may be scaleless it is never 
invested with bony plates. False gills may be developed, and, if so, are glandular. 
When an air-bladder is present, it is always of large size; and it may be divided 
into two lateral moieties enclosed in an ossified capsule, or constricted into an 
anterior and posterior portion which are not thus protected. The numerous 
members of this family are fresh-water fish, confined to the Old World and North 
America, being quite unknown in the southern half of the New World, and also in 
Australia. Showing much less diversity of form and habits than the cat-fishes, 
the carp tribe are for the most part omnivorous, although a few of its members 
restrict themselves to a vegetable diet. Although some of them prefer muddy 
situations, where their barbels are probably of assistance, the majority of the carps 
differ from the cat-fish in selecting clear waters for their haunts. The Indian 
forms seem to be more carnivorous than their European relatives, many of the 
larger kinds preying upon their smaller brethren. Geologically, the carps appear 
to be a comparatively modern group, the earliest known forms occurring in the 
Eocene of Sumatra; these being identified with existing Oriental genera. Other 
fossil carps have been obtained from the North American Eocene, and are assigned 
to extinct generic types; while in the Continental Miocene we find representatives 
of a number of the existing European genera, as well as of a few now mainly or 
exclusively Asiatic. On account of their more cleanly feeding-habits the flesh of 
the carps is superior to that of the cat-fishes. The family is represented by over 
a hundred existing genera, arranged under two subfamilies. 
True carps The common carp (Cyprinus ccirpio ) claims our attention as the 
typical representative of the subfamily Cyprinince, characterised by 
the air-bladder (wanting in one Oriental genus) not being enclosed in bone, and 
divided into an anterior and posterior moiety. In the Oriental genus ( Homalop- 
