THE AMERICAN BONY PIKE. 23 



a-half pairs of gills, but no gill upon the operculum. There is a spiracle on each side of the parietal 

 bone, covered by a bony plate. The branchiostegal rays are replaced by a single plate of bone. 

 The stomach has no blind sac, there is one pancreatic appendage, and the intestine terminates in a 

 spiral valve. There are fifty-one vertebrae in the abdomen and sixteen in the tail. 



From Old Calabar there comes a remarkable fish closely allied to the Polypterus, which is 

 named Calamoichthys calabaricus. It has a much more elongated form ; the dorsal and ventral sur- 

 faces are parallel. There are about a hundred vertebrae in the abdomen and ten in the tail. The 

 dorsal fin is represented by from nine to eleven finlets ; the ventral fin is absent, and the small anal 

 fin is placed at the hinder extremity of the body, immediately below the tail. 



FAMILY III. LEPIDOSTEID^E. THE AMERICAN BONY PIKE.* 



The Bony Pike, or Garfish, as it is often called, is one of the most distinctive of American 

 types of fish-life. It is met with in the rivers and lakes of the basin of the St. Lawrence, in various 

 parts of the United States, and in Mexico, and occurs in Cuba. American authors have distinguished 

 more than twenty diiferent species, which have been referred to several genera. Dr. Giinther 

 reduces these species to three the Lepidosteus viridis, the Lepldosteus pkitystomus, and Lepidosteus 

 osseus. These fishes swim with the greatest rapidity, darting through the lakes and rivers, and 

 are able to pass through the most rapid currents, not excepting the rapids of Niagara. Their 

 bodies are more flexible than those of ordinary fishes. Agassiz notices that the 



head moves freely on the neck, and may be indifferently wagged from side to side, 

 or moved upward or down, movements which are impossible in other fishes. 

 This mobility results from the remarkable mode of union of the vertebrae with 

 each other. Instead of being cupped at each end there is a rounded articular 

 surface in front, and a corresponding concavity behind. The vertebral column 

 terminates in a small conical cartilaginous rod, which is directed to the upper 

 margin of the tail, where it is only covered by the skin. The vertebrae have 



/ J VERTEBRA OF THE 



transverse processes, to which the ribs are articulated. AMERICAN BONY PIKE. 



The head has an armoured appearance, and is covered with furrows and 



rugosities, which are arranged in a definite manner ; it is prolonged into jaws, which are large and 

 long in proportion to the size of the hinder part of the head. The lower jaw is always rather shorter 

 than the upper, and is formed of the same bones as occur in the jaws of Crocodiles and Lizards. The 

 maxillaries are a series of bones joined together, end to end, so as to produce by their union a single 

 long bone. The snout includes, besides the maxillaries, long nasal bones and some other bony elements. 

 The fins unite with the skeleton, as in other osseous fishes. The pectoral fins are strongly developed. 

 All the fin-rays are jointed. The air-bladder is placed as in other fishes ; it communicates with 

 the throat by a duct, which is guarded by a circular muscle. This organ is very long, and extends 

 from the oesophagus to the hinder extremity of the body. It is forked in front, but is undivided 

 in the greater part of its length, and sometimes there is a trace of a posterior bifurcation ; it is said 

 to be muscular, so as to be capable of contracting. Its internal surface is cellular, so that it presents 

 some resemblance to the lungs of the lower reptiles and amphibians ; but while air is breathed by this 

 organ there are also gills, which are supported on four arches and have a bi-serial structure. The 

 branchiostegal rays are three in number. The scales, next to the long jaws, are the most striking 

 feature of the animal. They are lozenge-shaped, and arranged in more or less oblique series, so as 

 to overlap each other, and form a close-fitting bony armour. In the middle of the belly the scales 

 are heart-shaped. The external layer of the scales is always brilliant and shining, being formed of 

 enamel, while the lower layer consists of bone. The scales are perforated by canals similar to the 

 blood-vessels in bones, and the vessels passing through them carry blood to the skin. The lateral line 

 is always straight. The colour of the back is brownish-yellow or greenish, sometimes with black 

 spots. The young sometimes have a dark band at the sides, and generally a dark band in the 

 median line of the back. The nasal pores are at the extremity of the snout, and the eyes are a 

 moderate size. These fishes are extremely voracious ; they often frequent shallow and reedy places 

 and bask in the sun. They approach their prey slily and sideways. The prey is held in the mouth 



. * Genus Lepidosteus. 



