544 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 83 



ments 11 (in all 24 available specimens). Caudal segments modally 

 38, varying 36 to 39. Dorsal rays modally 19, varying 18 to 21. 

 Pectoral rays modally 16, varying 15 to 18. Spines on upper ridge 

 of trunk fairly well developed in full-grown fish, only slightly better 

 developed in female. Coronet fairly well developed; a humplike 

 bony elevation preceded by a spinelike tubercle in front of coronet, 

 the spine often becoming obsolescent, producing an effect of a double 

 hump, the latter usually fairly discontinuous and separated from 

 coronet, often nearly fused and having the effect of a very bi-oad 

 coronet when viewed laterally (resembling then that of multianmdaris, 

 see p. 540). Trunk of medium depth ; snout of medium length. Fila- 

 ments present in some of the specimens examined, relatively not 

 numerous, sometimes rather long (many long filaments shown on one 

 of Rauther's figures). Color (somewhat faded in the material ex- 

 amined) more or less profusely peppered with vrhite dots; somewhat 

 coarser, in form of very small white spots, on side of trunk and opercle ; 

 often coalescent there to form short, somewhat irregular elongate 

 spots or v/hite lines showing a tendency to a vertical arrangement on 

 trunk and on opercle. Dorsal with a dark submarginal band, dusky 

 below but of a lighter shade than the band. (See tables 1 and 2 for 

 counts and measurements.) 



Distinctive characters and relationships. — H. guttulaius is composed 

 of two subspecies, the typical subspecies in the Mediterranean, and 

 a second subspecies, multiannularis, on the Atlantic coast, which has 

 already been described. The difference between the two is discussed 

 on page 541. 



The subspecies H. guttulatus may be readily distinguished from the 

 other common seahorse occurring within its range, H. hippocampus, 

 by its more numerous caudal segments and dorsal and pectoral rays 

 and by its longer snout and slenderer trunk. All these characters 

 are discontinuous or nearly so (see tables 1 and 2), and there should 

 be no trouble in properly placing even individual fish. Fiu-thermore, 

 these differences are reinforced by guttulaius having notably better 

 developed tubercles and a different color pattern, consisting of white 

 dots and spots against a darker nearly uniform background, instead 

 of the typical dark spots against a lighter background in hippocampus. 



H. guttulatus is close to hudsonius from the American coast. In 

 fact, as far as the structural characters are concerned, they may well 

 be regarded as subspecies. The greatest divergence between guttula- 

 tus and hudsonius is in the average greater number of caudal segments 

 in the former, but there is much intergradation between the two 

 (see table 1). The trunk in guttulatus averages somewhat slenderer, 

 and there are other smaller differences (see tables 1 to 3). //. guttu- 

 latus, too, shows some color peculiarities. It has neither the brown 

 lines on the trunk and opercle, which are characteristic of the full- 

 grown hudsonius and its subspecies punctulatus and kincaidi, nor the 



