418 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



diculatus. Linton (1910, p. 60) also suggested that this character might 

 be of generic value. Vaz and Pereira in 1930 named the genus Para- 

 hemiurus with P. parahemiurus from Sardinella aurita in Brazil as type. 

 This genus is distinguished from Hemiurus by the muscular undivided 

 seminal vesicle. As suggested by Manter (1934, p. 304) and accepted by 

 Woolcock (1935), H. merus is a member of the genus Parahemiurus. 



P. merus has been collected by the writer from 9 different species of 

 hosts at Tortugas, Florida. Twenty-six specimens have been studied. 

 No differences between P. merus and the description of P. parahemiurus 

 can be detected except in the extent of the cuticular denticulations or 

 rings. Since their distribution on the 2 surfaces of the body is not indi- 

 cated by Vaz and Pereira, the "anterior fourth of the body" extent de- 

 scribed might apply only to the complete rings on the dorsal surface. I 

 consider that P. parahemiurus is a synonym of P. merus. 



Eight other species of Parahemiurus have been named. Differences 

 between some of these are slight and indicate that variations within a sin- 

 gle species should be better known. Specimens of H. ?nerus from Tortu- 

 gas indicate that egg size is variable in the species, at least in different 

 individuals. For example, eggs in three specimens measured 18 to 22 by 8 

 to 10 /x, 23 to 24 by 10 ix, and 30 by 10 /a; and Linton records 27 by 10 

 fx. The limits seem to be 18 to 30 by 8 to 10 /a in preserved specimens, 

 while Vaz and Pereira 's measurements would extend the width to 14 ju. 

 Another variable character is seen in the form of the vitellaria which 

 may be unlobed or slightly lobed. The uterus may or may not enter the 

 ecsoma. The cuticular denticulation seems fairly constant. The body 

 folds or rings extend entirely across the dorsal surface only as far back 

 as the acetabular region, whereas on the ventral surface they continue to 

 the level of the ovary or in some specimens to the posterior edge of the 

 vitellaria or, in a few specimens, slightly beyond (fig. 103). Near their 

 termination they become inconspicuous. There may be some variation as to 

 how far dorsally the plicae reach, but in both the Atlantic and the Pacific 

 material favorable to show this character they extend well around the 

 edges of the body as far back as the testes but do not meet dorsally poste- 

 rior to the acetabulum. The unringed dorsal area gradually widens pos- 

 teriorly (fig. 103). This denticulation is similar to that of most of the 

 described species but different from that of P. australis, probably P. an- 

 choviae, and the new species following. 



From these observations, I believe that P. platichthyi Lloyd, 1938 

 from Puget Sound is a synonym of P. merus. P. atherinae Yamaguti, 



