The cartilaginous Structures of the cmbryos of Hippocampus reidi Ginsburg, 1933, were described as well as the beginning of the ossification process in the dentary, angular, retroarticular, operculum, frontal, supraoccipital bonés and neural end hemal arches. The viteline sac is well developed. The results show that cartilaginous structures are predominam in specimens with an average of 4.85 mm in total length.
Hippocampus; seahorse; osteology; fishes