PIPE-FISHES. 



91 



either in a sac at the base of the tail, or attached to the abdomen. [Case 2) 

 The best known are the Pipe-fishes (Syngnathus) and the Sea-horses 

 (Hippocampus) . 



Tis. 79. 



Pipe-fish (Syngnathus acus). (From the Cornish coast.) 



The lower figure represents the pouch below the tail, opened on one side to 



show the young, which are ready to escape from the pouch. 



Order VI. PLECTOGNATHI. (Cases 25-27.) 



Teleosteous fishes with rough scales, or with ossifications of the 

 cutis in the form of scutes or spines ; skin sometimes entirely naked. 

 Skeleton incompletely ossified, with the vertebrse in small number. 

 Gills pectinate ; a narrow gill-opening in front of the pectoral fins. 

 Mouth narrow ; the bones of the upper jaw generally firmly united. 

 A soft dorsal fin, belonging to the caudal portion of the vertebral 

 column, opposite to the anal; sometimes elements of a spinous 

 dorsal besides. Ventral fin none, or reduced to spines. Air- 

 bladder without pneumatic duct. 



This Order consists of two families, Sclerodermi and Gym- 

 nodontes. 



The Sclerodermi comprise the genera Triacanthits, Batistes, Mona- 

 canthus, and Ostracion. The File-fishes (Batistes, fig. 80) inhabit 

 the tropical and sub-tropical seas; both jaws are armed with eight 

 strong incisor-like and obliquely truncated teeth, by which these 

 fishes are enabled to break off pieces of corals on which they feed, 

 or to chisel a hole into the hard shells of Mollusca, in order to 



