3 7 o Memoir Sears Foundation for Marine Research 



of mud in the stomach suggests that they also feed on the bottom. Stearns said, 

 "The Gulf menhaden are a bottom-feeding fish, as their stomachs always contain 

 soft brown mud, from which I suppose they extract microscopic animal and plant 

 matter" (^5). 



Parasites. As in Atlantic menhaden, the isopod Olencira praegustator (Latrobe) is 

 frequently found in the mouth of Largescale Menhaden {loy. 231). Stearns (^5) like- 

 wise reported it, saying: 



When the Gulf Menhaden arrive in spring, each one has a parasite in its mouth, a crustacean called 

 Cymothoa praegustator. This is found always in one position, clinging with its claws to the roof of the fish's mouth, 

 with its head looking forward and very near to the jaws of the fish. The parasites remain with the menhaden 

 as long as the latter is in salt water; in brackish water they are less frequently observed, disappearing altogether 

 in fresh water. With all the fall fish of this species which I have examined there were no parasites. 



Once more it is possible that Steam's observations may have been based on one or 

 both species inhabiting the Gulf. 



Two species of copepods, Bomolochus teres Wilson and Lernanthropus hrevoortiae 

 Rathbun, have been reported as parasitic on Gulf Brevoortia (12: 582, 588), but it is 

 not known whether one or both species served as host. 



Relationship. This species, closely related to tyrannus of the Atlantic coast, generally 

 has been considered identical to it or only subspecifically distinct. However, it differs 

 in so many respects from tyrannus that it apparently must be recognized as a distinct 

 species. Furthermore, the range of the two species is discontinuous, for neither occurs 

 in southern Florida, south of the Indian River on the Atlantic or south of Tampa on 

 the Gulf. 



The body depth in patronus compared with tyrannus is a bit greater, the shape is 

 different, the head and body are deeper anteriorly, and the ventral outline is notably 

 more strongly convex. The deepest part oi patronus' body is well in advance of the tips 

 of the pectoral fin and only about an eye's diameter behind the margin of the opercle, 

 whereas in tyrannus it usually is over the tip of the pectoral and notably more than 

 an eye's diameter behind the margin of the opercle. The differences in shape are 

 plainly evident in Figs. 86 and 91. Also, in patronus the fins generally are longer, 

 the scaly sheath on the base of the dorsal is broader, the axillary process of the pec- 

 toral usually is shorter, and the modified scales in front of the dorsal are larger and 

 have shorter pectinations; in fact, overlapping in the number of modified scales is 

 slight, occurring in only some of the rather numerous specimens examined. 



The extremes of variation, as well as the usual variation, are given in the Descrip- 

 tion, and from those data it is evident that some overlapping occurs in every proportion 

 and count. Nevertheless, the average differences are great in some of them. The more 

 outstanding ones are the following, with those for patronus given first (in per cent of 

 standard length): depth 38.8, 34.2; head (length) 33.6, 32.2; head (depth) 1Z-Si 27-8; 

 pectoral fin 20.9, 18.7; lower lobe of caudal 34.3, 29.4; vertebrae 45.8, 48.0; scales 

 along middle of side 41.7, 48.2 ; modified scales on back in advance of dorsal fin 28.0, 

 36.0; and ventral scutes 29.8, 32.5. 



