REVIEW OF HIPPOCAMPUS — GINSBURG 555 



Variability qf color, spines, and appendages with age, sex, habitat^ 

 and individual fish. — The development of filamentous processes varies 

 primarily with the individual and to a minor extent possibly with age. 

 Filaments, either simple or branched, are usually present in moderate 

 numbers on the postorbital spines and those of the coronet and the 

 upper ridge of the trunk; at least a few are present. Sometimes they 

 are quite profuse (fig. 64) or altogether absent. Wlien few they 

 sometimes take the form of short chunky appendages. Specimens 

 with a profusion of filaments were relatively more numerous in the 

 smaller size group, while specimens with a total absence of filaments 

 were comparatively more numerous among the larger fish; but this 

 difference is not pronounced. In either small or large specimens 

 filaments were sometimes profuse and sometimes altogether absent. 

 No appreciable difference with sex in the development of filaments 

 was noted. Small specimens often have very many tablike skinny 

 processes, pimplelike excrescences, and short filaments, besides those 

 on the spines, generally distributed on the head, trunk, and to a lesser 

 extent on the tail. With growth the tabs, pimples, and shorter 

 filaments mostly disappear. 



The spines in the young (three specimens 17 to 24 mm from North 

 Carolina examined; fig. 60) are strongly and very unequally developed; 

 generally every alternate spine on the trunk and every tliird or fourth 

 spine on the upper margin of the tail are inordinately long. These 

 greatly elongate spines rapidly decrease in length with growth (in two 

 specimens 32 and 33 mm the spines are considerably shorter but 

 still relatively somewhat longer as compared with larger specimens). 

 The relative decrease in the length of the spines with growth is some- 

 what unequal in the two sexes. In general, in seahorses taken in 

 comparatively shallow water, the spines are appreciably but not 

 strikingly unequal in males of about 50 mm long (fig. 61) and females 

 of about 60 mm long. In full-grown specimens the spines are gecer- 

 ally reduced to form shorter tubercles, which are either subequal or 

 not strikingly unequal and rather short although usually well devel- 

 oped as compared with most other species or subspecies of Hippo- 

 campus. Even in full-grown specimens the tubercles are relatively 

 somewhat better developed in females than in males, this condition 

 being more or less evident also in the other species (see p. 509). 

 Development of the spines or tubercles varies to a large extent with 

 individual fish at any given size. Consequently, the foregoing 

 remarks apply only in a general way, with frequent exceptions. 



Medium-sized specimens frequently occur with unusually well 

 developed tubercles or rather long spines (fig. 64). Such specimens 

 occur all along the coast including the geographic range of both 



