REVIEW OF HIPPOCAMPUS — GINSBURG 499 



"belief", thrco more or less common and large species exist on the 

 Atlantic coast of the United States, namely, H. hudsonius, H. punc- 

 tulatus, and H. stylifer, which allegedly may be distinguished largely 

 by the number of rays in the dorsal fin, hudsonius having the most 

 rays and stylijer the least. It will be shown definitely hereafter that 

 stylifer is a fictitious species based originally on a young female of 

 pundulatus, while hudsonius and punctulatus are merely geographical 

 subspecies that intergrade to a high degree; and, moreover, that 

 hudsonius is the one averaging the fewest dorsal rays. 



The student will find similarly striking cases in the text, but for 

 benefit of readers who do not wish to delve too deeply into the syste- 

 matics of Hippocampus, one more interesting illustration may here 

 be cited. Nearly all authors correctly distinguished two common 

 species of seahorses, hippocampus (brevirostris of most authors) and 

 guttulatus, from the Mediterranean coast of Europe. These two species 

 are readily separable, as is shown hereafter. However, the systematics 

 of the seahorses on the Atlantic coast of Europe are generally muddled. 

 An inclusive, though probably incomplete, review of the literature 

 shows that the consensus of opinion among authors is that only one 

 species of seahorse exists on the Atlantic coast of Europe. This 

 allegedly single species has been referred now to one now to the other 

 of the two common Mediterranean species, depending on the author. 

 This treatment is evidently not in accordance with the facts. My 

 study indicates, if the stated localities of the lots examined are correct, 

 that at least two species of seahorses exist on the Atlantic as well as 

 on the Mediterranean coast of Europe, but the two Atlantic species 

 are not so readily separable as the Mediterranean ones. One of the 

 Atlantic coast species is closely related to but distinct specifically 

 from hippocampus and is designated hereafter as europaeus. The 

 other Atlantic seahorse is apparently conspecific with guttulatus from 

 the Mediterranean, but the Atlantic coast population diverges suf- 

 ficiently to be regarded as subspecifically distinct from the Mediter- 

 ranean population, and is designated herein as multiannularis. Since, 

 however, part of the European seahorses in American museums that 

 were available for examination are in indift'erent condition and the 

 locality records of some of the lots are uncertain, the conclusions 

 regarding the European species arrived at may have to be modified 

 after an examination of larger numbers of specimens in good condi- 

 tion and with definite locality records. However, my study and a 

 review of the literature showed without doubt that the current syste- 

 matic treatment of the seahorses found on the Atlantic coast of 

 Europe is largely erroneous. 



The confusion in the systematics of Hippocampus is shown even 

 more strikingly by the obvious and frequent misapplication of names 



