BULLETIN OF THE UNITED STATES FISH COMMISSION. 281 



to believe that in this sea it could obtain, in great abundance, the pe- 

 culiar food adapted to its wants.* 



Once successfully introduced, in numbers sufficient to sustain the 

 species against the natural causes of destruction, it must become abun- 

 dant. For tlie temperature of the gulf-stream opposing, according to 

 recent experiments, an irremovable barrier to its exit, its oceanic range, 

 on the western side of Florida, would be limited to the body of cold 

 water, the boundaries of which have been described.t 



Many of the rivers that pour their contents into this belt would seem 

 to be as well adapted to the functions of reproduction as any the shad 

 naturally frequents. Let us take for comparison the Ockmulgee — one 

 of the branches of the Altamaha, a river of Georgia — and the Flint 

 Kiver, a tributary of the Apalachicola, which flows through western 

 Florida into the Gulf of Mexico. 



These streams have their origin in the same State, and spring from a 

 geographical range which is geologically the same. At one point they 

 almost touch. Now the Ockmulgee, like its sister tributary, the Oconee, 

 teems with shad ; while in the Flint Eiver they are unknown. Yet they 

 are in juxtaposition, and their waters, for the practical purj^oses of this 

 deduction, are homogeneous. One makes its way to the Atlantic Ocean, 

 where shad abound; the other to the Gulf of Mexico, where they do not 

 exist. 



But be the possibility of its successful introduction into the Gulf what 

 it may, such, as has been shown, is the food of this fish; and such, with 

 deference to the opinions of others, are the functions of the coeca. 



These assertions rest on — 



1. Th^ examination of twenty-five or thirty shad obtained from Sa- 

 vannah, Ga, at different times, from February 2d to March 15th, of this 

 year (18G0). In three specimens only were the stomachs entirely empty, 

 and in these the cceca were greatly distended. 



2. Nineteen stomachs with their contents dried, and glued to glass 

 with Canada balsam. In all of which are to be seen the fuci and shells 

 of infusoria, and in one numerous cylindrical stalks of algae are plainly 

 to be recognized by the naked eye. 



3. A part of one of the coeca opened, and flattened out on a slide, the 

 dried contents resting on the mucous membrane. With a glass of higher 

 power, sparkling i)oints of the calcareous discs, which have escaped the 

 action of the gastric juice, may be seen, here and there, in the thinnest 

 parts of this specimen. 



4. A parasite from the mucous surface of the above ccecum, identical 

 with one taken from the conical stomach of the same fish. 



* Since this pamiihlet was in-inted I have discovered in the stomach of a species of 

 Alosa, very uumeious in the Gulf of Mexico, fucus and shells identical with those found 

 ill the Atlantic shail. 



t Sec a paper by Mr. Wm. Gessner, of Milledgeville, Ga., in August No. of the Cotton 

 Planter and Soil, p. 256, Montgomery, Ala., 1858. 



