LIFE insroRY OF SEA-HORSES— GILL. 



809 



to note that Dufosse found that the fishes had the powei- of making 

 long series of movements so slight and so rapid that they evade tlie 

 sight, but are appreciable to touch, and consequently are simple quiver- 

 ings or vibrations (fremissements), and that these quivering move- 

 ments are accompanied ))y sounds which, however, are I'arely distinctly 

 audible (commensurablcs). The soiuids are produced by females as 

 well as males; notably in the spawning season, when they are both 

 more frequent and more intense. 



IV. 



The natural food of the sea-horses consists mainly of small crusta- 

 ceans, such as copepods, sand-fleas {Gfuitm((r!dH)^ and the opossum 

 shrimps {^[yxidx) as well as the young of higher forms. Such being 

 not readily obtainable by aquarium keepers, 

 Kent improvised for his acjuaria "a suc- 

 cessful substitute in the form of the larvae 

 of the common gnaf or mosquito {Ciilex 

 pij>!en.s) and '•"other water insects."" 



The mode of feeding is curious. A sup- 

 ply of amphipodous crustaceans may be 

 supplied to them and a fish will slowly 

 move toward one, peering at it, approach- 

 ing the mouth to it, and suddenly the ani- 

 malcule may disappear without an}^ per- 

 ceptible movement of the jaws as though 

 the fish had sucked it in. But the aniphi- 

 pod (or other animal) must be at rest or on 

 the ground or a plant; for the fish is too 

 slow to get one moving; nevertheless it 

 must be alive. The fish may throw itself 

 on its side or in any other attitude most fit 

 to o'et hold of the coveted "l)uo-." 



As the season for reproduction approaches fig. 5.— sea-horse (Hippocampus 



,1 1 J !• -A fTM HUDSONIUS). Male WITH DILATED 



the sexes become prepared for it. The ^^^^^^ (after kaup.) 

 mature female's cloaca or "genital papilla" 



is somewhat extended and becomes a kind of intromittent organ for the 

 transfer of her eggs to the male. The receptive male's pouch becomes 

 thickened and vascular and thus prepared for the reception of the 

 eggs and the nutriment of the embryos. The males, as usual in fishes, 

 are somewhat smaller than the females. 



«The many sea-horses in the atjuaria at St. Louis (1904) were fed ahnost entirely 

 on the larvae of trout and sahuon; the yelk-sac of the latter was broken before the 

 larva could be swallowed. 



