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A rather unique performance, partic- 
ularly for one to witness a thousand 
miles from the shore of the ocean, took 
place in my marine aquarium on October 
5th. Myself and another member of 
the Chicago Aquarium Society were for- 
tunate in being present when about one 
hundred baby sea horses, Hippocampus 
hudsonius, left the parental pouch. 
The male, when he arrived, displayed 
an enormously distended abdomen, 
which protruded in every direction ex- 
cept toward the back. He was so mis- 
shapen that the vent and anal fin ere 
fully an inch above the position not -d 
in normal specimens. On the evening 
of October 5th the lower portion of ite 
protuberance, previously black, develop- 
ed a dark yellowish color. Contortions 
and twistings began, which gradually 
changed to regular backward and_ for- 
ward labor convulsions. These effur:s 
from time to time (between periods of 
rest), resulted in the expulsion of the 
babies. From one to four were expelled 
in a delivery, the opening being round 
and a quarter of an inch in diameter, giv- 
ing a fairly clear view of the cavity. The 
youngsters were curled when expelled, 
but immediately straightened out and 
sank to the bottom, where they lay on 
their sides, wriggling at times rather 
violently. The babies were equipped with 
a yolk-sac and were pinkish in color, 
otherwise they resembled the parents. 
In order to determine the proper en- 
vironment for rearing, some were placed 
in a shallow glass vessel with one inch 
of still water; others in deep still water. 
Another lot was placed in shallow water, 
provided with an aerator, and the aquar- 
a OS, 8 9S SP 6 9 PS Os Oa 8 7 8 Fs Pn a Ft $a i a S| 
| HIPPOCAMPUS 
ERWIN O. FREUND 
of 
HUDSONIUS | 
ad 
ium placed on an electric heating pad to 
ensure an even temperature. The re- 
maining babies were left with the par- 
ents. 
On the second day the parents ate 
those left with them, all being devoured 
in two hours. Those in the other vessels 
absorbed the yolk-sac in forty-eight 
hours. The fry in the shallow aerated 
Hippocampus hudsonius 
water died on the second day. Those in 
deep water on the third day. Those in 
the shallow still water on the fourth day. 
The male parent died on the fourth 
evening. Soon after the convulsions 
ceased the abdomen became covered by 
a gelatinous-like membrane, which turn- 
ed a yellowish-white and developed bub- 
bles. He entwined his tail about his 
favorite branch on the coral reef and 
remained there motionless until he died. 
A post mortem examination revealed 
several young and evidence of infection. 
Though I have been advised by Mr. 
