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PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 83 



sippi to Texas are intermediate between the extreme northern and 

 the extreme southern fish. In view of the high degree of inter- 

 gradation in all the characters studied and the evident gradual 

 change in these characters with latitude, there may seem to be good 

 reasons for treating them all under a single heading. Nevertheless, 

 while the^'^ do intergrade, the differences between the populations are 

 numerous, and typical large specimens from the extremes of their 

 geographical range may usually be identified without recourse to 

 locahty records. Also, among the species of Hippocampus there 

 exists a general condition of nearness of approach or even of over- 

 lapping. The populations from the extremes of the geographic range 

 should therefore be recognized as subspecies, punctulatus and hud- 

 sonius, the latter for the large seahorses occurring on the coast of the 

 United States north of Florida. 



Only one other species of seahorses, regulus, occurs within the 

 geographic range of hudsonius as limited in the present paper, and 

 it is easy to distinguish the two, regulus having much fewer segments 

 and fin rays (see p. 589). H. hudsonius is also very near to the Euro- 

 pean species guttulaius and europaeus. The differences between 

 them are discussed under the accounts of those species; in actual 

 practice hudsonius may be distinguished from the European species 

 by locality. 



Table 4. — -Averages of the numbers of caudal segments and fin rays of the subspecies 

 kincaidi, punctulatus, and hudsonius and the populations of hudsonius, cal- 

 culated from the frequency distributions given in table 1 



Subspecies and population 



Caudal 

 segments 



Dorsal 



rays 



Pectoral 

 rays 



kincaidi: Bermuda 



■punctulatus: Florida and Cuba 



hudsonius: 



North and South Carolina. 



Mississippi to Texas 



Virginia to Maine.. .-. 



34.8 

 35.9 



36.5 

 36.7 

 37.1 



18.3 

 19.3 



18.6 

 18.7 

 18.5 



16.0 

 16.4 



15.8 

 16.1 

 15.3 



Populations. — While the material studied is insufficient for a thor- 

 oughgoing racial analysis, a comparison of the averages of the caudal 

 segment and fin ray counts is highly suggestive and indicates that 

 the subspecies hudsonius is composed of three distinct stocks. This 

 is shown in table 4, wliich conveniently includes also the two related 

 subspecies, punctulatus and kincaidi, for comparison. A study of 

 table 4 together with table 3 shows that the population of hudsonius 

 from the coast of North and South Carolina differs from that of Chesa- 

 peake Bay and northward in averaging fewer caudal segments, more 

 numerous dorsal and pectoral rays, a deeper trunk, and a somewhat 

 longer snout. The Gulf coast population, that from Mississippi to 



