REVIEW OF HIPPOCAMPUS — GINSBURG 529 



^2. Development of tubercles on upper ridge peculiar, low, stout, and 

 blunt, not pointed, not obsolescent; in form of low knoblike stumps. 

 Slender, depth in medium-sized specimens not over 13.7 percent, 

 e^ Dorsal rays 17; caudal segments 35. Atlantic coast of United 



States obtusiis (p. 576) 



e*. Dorsal rays 20 to 21; caudal segments 39. Pacific coast of Panama. 



hildebrandi (j). 579) 

 c*. Trunk segments 10 (one specimen examined) . Tubercles well developed 



and pointed. With large blotches. Trunk deep villosus (p. 582) 



(i^. Dorsal rays 10 to 14. Pectoral rays 10 to 12. Upper ridges of trunk and 

 tail normally overlapping on one segment, infrequently on two, rarely on 

 none. First caudal segment oftenest quadrangular, sometimes hexan- 

 gular (an infrequent individual variation in regulus, frequent in zosterae). 

 Base of dorsal normally over two segments, usually the last two trunk 

 segments, sometimes over the first caudal and last trunk segments. Trunk 

 segments usually 10, sometimes 9, infrequently 11. Caudal segments 28 



to 34 r. Subgenus JAMSUS (p. 584) 



bK Dorsal rays with mode decidedly at 11, varying 10 to 12. Caudal segments 

 usually 29 to 31, varying 28 to 32. Trunk segments nearly always 10. 

 Maximum size 34 mm. Mississippi and Texas coasts; Campeche, 



Mexico regulus (p. 584) 



b^. Dorsal rays with mode decidedly at 12, varying 11 to 14. Caudal segm.ents 

 usually 31 to 33, varying 30 to 34. Trunk segments 9 or 10 (depending 

 on the racial stock), sometimes 11. Maximum size 44 mm. Florida, 

 Biscayne Bay to Pensacola zosterae (p. 5S9) 



Subgenus Macleayina Fowler 



Macleayina Fowler, Proc. Acad. Nat. Sci. Philadelphia, vol. 59, p. 426, 1907. 

 (Genotype: Hippocampus abdominalis Lesson = //. bleekeri Fowler by 

 original designation.) 



This subgenus was originally established on the basis of the in- 

 creased number of dorsal rays. Correlated with this is the position 

 of the dorsal base, usually on one caudal and five trunk segments. 

 It also differs in having the upper ridges of tail and trunk overlapping 

 normally on three segments instead of on two, the dominant condition 

 in the subgenus Hippocampus. While this difference may seem slight, 

 it is correlated with a more fundamental difference in structure, each 

 segment on which the two ridges overlap also having an extra plate 

 on top for the support of the dorsal (see pp. 505 to 507). In this respect 

 the species ingens is somewhat intermediate between Macleayina and 

 Hippocampus. Macleayina also has an increased number of caudal 

 segments and a higher average number of trunk segments. According 

 to McCulloch ^^ it contains five species. Of the species listed by 

 McCulloch, however, bleekeri and agnesae have been synonymized 

 with abdominalis by Fowler,^'' while graciliformis has been placed in 

 the synonymy of the same species by Waite and Halc^" The one or 



3S Mem. Australian Mus., vol. 5, p. 97, 1929. 



39 Proc. Acad. Nat. Sci. Philadelphia, vol. 73, p. 446, 1921. 



« Rec. South Australian Mus., vol. 1, p. 319, 1921. 



73864—36 3 



