Calamostoma of the Eocene, Gasterotokeus of Polynesia, and
Acentronura of Japan are forms which connect the true sea-
horses with the pipefish. Gasterotokeus has the long head
and slender body of the pipefish, with the prehensile finless


452


Phthinobranchii


Fic. 357. —Solenostomus cyanopterus Bleeker.
Misaki, Japan.
a


oe


Phthinobranchii 453


tail of a sea-horse. Most of the living species of the sea-horse
belong to the genus Hippocampus. These little creatures
have the egg-sac of the male under
the abdomen. They range from
two inches to a foot in length and
some of the many species may be
found in abundance in every warm
sea. Some cling by the tails to
floating seaweed and are swept to
great distances; others cling to eel-
grass and live very near the shore.
The commonest European species
is Hippocampus hippocampus. Most
abundant on our Atlantic coast is
Hippocampus hudsonius. Hippo-
campus coronatus is most common
in Japan. The largest species, ten
inches long, are Hippocampus in-
gens of Lower California and kel-
loggt in Japan. Many species, es-
pecially of the smaller ones, have
the spines of the bony plates of the
body ending in fleshy flaps. These
are sometimes so enlarged as to
simulate leaves of seaweed, thus
2 serving for the efficient protection
Hig. 358,—Sea-horse, Hippocampus Of the species. These flaps are

Saree ee EA developed to an extreme degree in
Phyllopteryx eques, a pipefish of the East Indies.
No fossil sea-horses are known.
