278 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



cause, is a very striking sight, aud with a little care the particles may be followed 

 up to and into the mouth. 



In order to trace the course of the digestive organs, the visceral mass may be split 

 with a sharp knife or razor. If the split is pretty near the middle of the body each 

 half will show sections of the short, folded esophagus, running upward from the 

 mouth, aud the irregular stomach, cut 1, s, with thick, semi-transparent walls, sur- 

 rounded l)y the compact, dark-greenish liver, 1 1. Back of the liver and stomach the 

 convoluted intestine, i, will be seen, cut irregularly at several points by the section. 



There are no accessory organs of reproduction, and the position, form, and general 

 appearance of the reproductive organ, plate i, fig. 2, is the same in both sexes. As the 

 reproductive organ has an opening on each side of the body, it is usually spoken of 

 as double, but in the adult oyster it forms one continuous mass, with no trace of a 

 division into halves, and extends entirely across the body and (against) the bends 

 and folds of the digestive tract.* 



Cut 1. 



The stomach is pretty definitely marked off" from the other portions of the digest- 

 ive tract. It may be said to be that portion of the latter which is surrounded by the 

 liver. The portion of the intestine immediately following the short, widened region 

 which we regarded as the stomach is the most spacious portion of the gut, and in it 

 is lodged a very singular organ, which has been called the " crystalline style." This 

 is an opalescent rod of a glass-like transparency and gelatinous consistence, which 

 measures according to the size of the oyster from half an inch up to one and a half 

 inches in length. Its anterior end is the largest, and in a large specimen measures 

 nearly an eighth of an inch in diameter, but at its jiosterior end is scarcely half as 

 thick; both ends are bluntly rounded. I fell into an error in supposing that this 

 style was lodged in a special pouch or sac, as described in my report to the Maryland 

 commissioner in 1880. The "crystalline style" really lies in the first jiortion of the 

 intestine and extends from the pyloric end of the stomach to the first bend of the 



* Brooks, W. K. Studies from the Biological Laboratory of Johns Hopkins Univer- 

 sity, No. IV, 1888, pp. 5-10 in part. 



