380 Memoir Sears Foundation for Marine Research 



of Texas where this species seems to be common, and it is not known whether it is 

 included among the menhaden processed in Mississippi. Neither is it known to what 

 extent _f««/m may have contributed to the reported Texas catches of 47,190,800 pounds 

 of "menhaden" for 1950, 30,121,200 pounds for 1951, 52,983,600 pounds for 1952, 

 and 589,300,000 pounds for 1953. Because of the extreme thinness of the fish, it 

 probably would not yield much oil. 



Range. Grand Isle, Louisiana, to the mouth of the Rio Grande, Texas. 



Synonyms and References: 



Brevoortia fatronus Goode (in part B.gunteri Hildebrand), Proc. U. S. nat. Mus., I, 1879: 39 (diagn., tables 



based in part on B.gunteri). 

 Brevoortia sp. Gunter, Publ. Inst. mar. Sci. Texas, J (i), 1945 : 27 (second species from Gulf, but not named; 



relation with other Brevoortia spp.; habitat, food, habits, spawn.). 

 Brevoortia gunteri Hildebrand, Smithson. misc. Coll., loy (18), 1948: 31, fig. 7 (orig. descr.; t^pe local. Aransas 



Bay, Texas; type USNM 129798). 



Genus Opisthonema 1861 



Opisthonema Gill, Proc. Acad. nat. Sci. Philad., 1861: 37; genotype by original designation, O.thrissa Gill 

 equals O. oglinum (LeSueur).*" 



Characters. Body elongate, well compressed, its greatest depth exceeding length 

 of head. Bony scutes with sharp points, about 32-36 on sharp edge of chest and ab- 

 domen. Cheek notably longer than deep. Vertical part of Clavicular margin (under- 

 neath opercle) with two small projections or lobes. Mouth of moderate size. Maxil- 

 lary failing to reach middle of eye. Upper jaw without definite median notch. Lower 

 Tiw projecting beyond the upper. Teeth missing. Dorsal with about 17-21 rays, 

 the last ray greatly produced, often reaching nearly to base of caudal. Anal with about 

 20-25 rays, the last one not greatly enlarged. Pelvic fin with 8 rays, inserted under 

 base of dorsal fin, generally well behind origin of dorsal. Pectoral without an axil- 

 lary process, lying in a slight depression. Vertebrae about 46-48. 



Remarks. The chief distinguishing characters are the large dorsal fin, with nearly 

 or equally as many rays as the anal and with the last ray greatly produced, frequently 

 so that it reaches nearly or quite to the base of caudal ; the projecting lower jaw with 

 its abruptly ascending upper margin within the mouth; the long shallow cheek; the 

 small pelvic, with 8 rays, inserted behind the origin of the dorsal ; and the absence of 

 a process (scale) in the axil of the pectoral. 



Range. The genus is known on the Atlantic coast of America from Cape Cod, 

 Massachusetts, to southern Brazil, and from the West Indies. On the Pacific coast it 

 is known to range from the Gulf of California to Peru. 



42. It is probable but not certain that Gill intended this generic name for the fish now known as O. oglinum. Clupea 

 thrissa Linnaeus {84: 318) has been applied to both a Chinese and an American species, which many older authors 

 considered identical; at the time Gill wrote (1861), they were generally so considered. In fact it was not until 1917 

 that they were properly separated. Regan {106: 308) cleared up the confusion, and Herre and Myers (56: 234) 

 have diagnosed still more carefully the Chinese Clupanodon thrissa. — G. S. M. 



