680 FISHES. 



ventrals, and, somctiincs, one or more of the other fins are also 

 absent. 



Small marine fishes, wliicli are abundant on such parts of 

 the coasts of the tropical and temperate zones as offer by 

 their vegetation shelter to these defenceless creatures. They 

 are iDad swimmers (the dorsal fin being the principal organ 

 of locomotion), and frequently and resistlessly carried by cur- 

 rents into the open ocean or to distant coasts. All enter 

 brackish water, some fresh water. The strata of Monte Bolca 

 and Licata (Sicily) have yielded evidence of their existence 

 in the tertiary epochs; beside species of Siphonostoma and 

 Syngnatlius (PseudosT/n/jnathus), remains of an extinct genus, 

 Calamostoma, allied to Hvpi^ocamiyus, but with a distinct 

 caudal fin, have been found. On their propagation see 

 p. 163, Kg. 76. 



A. Syngnathina. — The tail is not prehensile, and generally 

 provided Avith a caudal fin. — Pipe-Fishes. 



SiPHONOSTOMA. — Body with distinct ridges, the upper caudal 

 ridge continuous with the lateral line, but not with the dorsal 

 ridge of the trunk. Pectoral and caudal fins well developed ; 

 dorsal fin of moderate length, opposite to the vent. Humeral 

 bones movable, not united into a " breast-ring." Males with 

 an egg-pouch on the tail, the eggs being covered by cutaneous 

 folds. 



Two species, of which 8. typlile is common on the British, 

 and generally distributed on the European coasts. 



Syngnathus. — Body with the ridges more or less distinct, 

 the dorsal ridge of the trunk not being continuous with that of 

 the tail. Pectoral fins well developed ; caudal present. Dorsal 

 fin oi^posite or near to the vent. Humeral bones firmly united 

 into the breast-ring. Egg-pouch as in Siphonostoma. 



The distribution of this genus nearly coincides with that 

 of the family, some fifty species being known. S. acus, the 

 great Pipe-fish (see Fig. 75, p. 163), is one of the most 

 common European fishes, extending across the Atlantic and 



