THE DISCOBOLI. 75 



nearly straight, and is so short that its length is only about one third of the 

 distance from its anterior extremity to the forward end of the chain, and it 

 rises backward to meet the preoperculum. The latter is less expanded in the 

 upper limb than in the other species ; the hinder prolongation of the oper- 

 culum is more turned upward ; the suboperculum is raoi'e slender, and its 

 branches form a more acute angle between them ; and the interoperculum 

 is more bent upward posteriorly. As on the other species, in the base of 

 the pectoral, scapula, carpals, and coracoid form a series of six bones, each 

 of which is in contact with the clavicula. With the close attachment exist- 

 ing between the inside of the base of the pectoral and the side of the body 

 the motion of the fin is almost entirely confined to the rays, which have 

 sufficient freedom of movement on the edges of the basalia. The post- 

 clavicula is very long and slender. In the base of the caudal of the speci- 

 men under examination a peculiar feature is to be observed : viewed from 

 the side, the posterior vertebral segment bears some likeness to the end 

 of the column as shown in Figure 4 of Plate XII., except that, instead of 

 rays passing from the lower edge of the strong backward and upward 

 directed spine-like termination, there are two thin plates which widen 

 backward toward their subtruncate hinder margins, on which the caudal 

 rays are joined. Both of the plates pass from the lower edge of the so 

 called spine, which ends in the superior hinder angle of the upper plate. 

 An embryonic simulation is brought about by this spine and the greater 

 length of the upper plate. 



Viscera. — There is a partial division of the liver into three lobes. The 

 greater portion lies to the left side, and has the appearance of being two 

 lobes, the lower longer, broader, and rounded posteriorly, the upper shorter, 

 narrower, and more pointed. A third portion lies toward the right; it is 

 the shortest, and is sinuate on the hind border. The gall bladder is small, 

 elongate, and empties into the intestine a short distance below the casca. 

 The stomach is shaped a little like a " Dutchman's pipe " ; the cardiac por- 

 tion (bowl) is larger and twice as long as the pyloric. Half of the cardiac 

 portion, thin-walled and darker colored, is a mere recejjtacle for the food ; 

 in the posterior half, in which the digestive function resides, the walls sud- 

 denly thicken and change in color, becoming white, like the pyloric region. 

 There is no constriction, as if the anterior part were a continuation of the 

 esophagus, as might be expected between two sections so different in thick- 

 ness of wall and in color. The pyloric portion is only about half as long 



