b LOPHOBRANCHII. 



first dorsal and ventrals wanting. Anal fin very small, almost 

 imperceptible or altogether wanting. The males carry the eggs 

 in a pouch on the breast and belly, or in one on the tail, or 

 placed on the skin of the breast and belly in rows. In some 

 genera there are no egg-pouches, and we are as yet ignorant of 

 the manner of their propagation. Such are the genera Soleno- 

 gnathus and Phyllopieryx. 



Subfam. 1. HIPPOCAMPINiE, Bon. 



Diagn. — Tail generally prehensile at the tip, destitute of fins. 

 Occiput more or less elevated. 



Genus 1. HIPPOCAMPUS, Cuv. 



Diagn. — The more or less elevated hind-head, with an occipital 

 bone bearing a coronet surmounted by spines and knobs. 

 Orbits spiny. Breast-ring with 2 or 3 spines. Body having 

 from 10 to 13 rings more or less spiny. Tail-pouch of 

 the males formed of thick skin, and opening at its com- 

 mencement only. Tail prehensile like that of the Chame- 

 leon. 



Descr. — Body heptagonal, laterally compressed; breast and 

 belly acutely ridged. The lateral line connected with the under 

 tail-ridge. The upper tail-ridge reaching as far as the middle of 

 the dorsal fin ; that fin generally rests on three rings, but in some 

 species on four, five, or six, of which one or two only belong to 

 the tail. The quadrangular tail exceeding the bodj- in length. 

 The spines and knobs on the body are generally more prominent 

 in the young fish than in the old ones. Within the small opening 

 of the egg-pouch the anal fin often lies hidden. All the males, 

 without exception, have this fin, but it is frequently overlooked. 

 The function of the prehensile tail is to suspend the body after the 

 manner of the Chameleon or Cebus. Like the Chameleon also, 

 the Seahorse-fish can direct one eye forwards and the other 

 backwards. Professor Lichtenstein (Wiegm. Archiv, 1836, 

 p. 129) observed a circular movement in the water, near the gill- 

 openings ; on the right side the whirl revolved to the left, and 

 on the left side to the right, the rotation being symmetrical and 

 constant like that of a Rotifer as seen under the microscope. 



The Hippocampi inhabit every sea. 



