=Suborder Synentognathi.=—Among the transitional forms between the soft-rayed and the spiny-rayed fishes, one of the most important groups is that known as _Synentognathi_ (σύν, together; ἔν, within; γνάθος, jaw). These have, in brief, the fins and shoulder-girdle of _Haplomi_, the ventral fins abdominal, the dorsal and anal without spines. At the same time, as in the spiny-rayed fishes, the air-bladder is without duct and the pectoral fins are inserted high on the side of the body. With these traits are two others which characterize the group as a suborder. The lower pharyngeal bones are solidly united into one bone and the lateral line forms a raised ridge along the lower side of the body. These forms are structurally allied to the pikes (_Haplomi_), on the one hand, and to the mullets (_Percesoces_), on the other, and this relationship accords with their general appearance. In this group as in all the remaining families of fishes, there is no mesocoracoid, and in very nearly all of these families the duct to the air-bladder disappears at an early stage of development. [Illustration: FIG. 165.—Needle-fish, _Tylosurus acus_ (Lacépède). New York. ] =The Garfishes: Belonidæ.=—There are two principal groups or families among the _Synentognathi_, the _Belonidæ_, with strong jaws and teeth, and the _Exocœtidæ_, in which these structures are feeble. Much more important characters appear in the anatomy. In the _Belonidæ_ the third upper pharyngeal is small, with few teeth, and the maxillary is firmly soldered to the premaxillary. The vertebræ are provided with zygapophyses. The species of _Belonidæ_ are known as garfishes, or needle-fishes. They resemble the garpike in form, but have nothing else in common. The body is long and slender, covered with small scales. Sharp, unequal teeth fill the long jaws and the dorsal is opposite the anal, on the hinder part of the body. These fishes are green in color, even the bones being often bright green, while the scales on the sides have a silvery luster. The species are excellent as food, the green color being associated with nothing deleterious. All are very voracious and some of the larger species, 5 or 6 feet long, may be dangerous even to man. Fishermen have been wounded or killed by the thrust of the sharp snout of a fish springing into the air. The garfishes swim near the surface of the water and often move with great swiftness, frequently leaping from the water. The genus _Belone_ is characterized by the presence of gill-rakers. _Belone belone_ is a small garfish common in southern Europe. _Belone platura_ occurs in Polynesia. The American species (_Tylosurus_) lack gill-rakers. _Tylosurus marinus_, the common garfish of the eastern United States, often ascends the rivers. _Tylosurus raphidoma_, _Tylosurus fodiator_, _Tylosurus acus_, and other species are very robust, with short strong jaws. _Athlennes hians_ is a very large fish with the body strongly compressed, almost ribbon-like.