162 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



and the gastrolith, and in front by the anterior lateral bar. The 

 lower edge of this plate forms a large fold, the lower lateral pad, 

 which overlaps the ventral surface of the stomach so as to enclose 

 on each side a deep groove which extends the whole length of the 

 ventro-lateral cardiac bar, i. e., from the oesophagus to the pyloric 

 sac. 



The ventral surface of the sac is raised into a low narrow median 

 ridge which ends abruptly above the ventral cardiac plate in a 

 rounded point. Near the middle of this ridge, there begins on each 

 side a ridge which quickly becomes higher posteriorly and, meeting 

 its mate, the two spread out in a broad deeply channeled elevation, 

 the cardio-pyloric valve, which has, in addition to its bilobed chan- 

 neled anterior portion, a median posterior lobe. Its anterior surface 

 is covered with a close pile of short, strong, upwardly and back- 

 wardly directed bristles, and the posterior lobe is armed with long 

 upwardly directed bristles. The posterior portion of the lower edge 

 of the lower lateral pad and the posterior edge of the middle lateral 

 pad overlap the edges of the cardio-pyloric valve. 



Each of the two grooves between the ventral and lateral walls of 

 the cardiac sac is divided by a row of long, large, close-set, back- 

 wardly inclined bristles into two canals; an upper and outer, the 

 upper cardiac canal, and a lower and inner, the lower cardiac canal. 

 The bristles of the ventral ridge and of the lower lateral pad interlock 

 so as to enclose both of these canals and the bristles separating them 

 interlock with the bristles of the lower lateral pad, so that material 

 can enter the upper cardiac canal only by passing through the lower 

 canal and between the bristles which separate the canals. The outer 

 and upper wall of the upper canal is smooth, while the lower and 

 inner wall of the lower canal is closely beset with very short, heavy, 

 upwardly-pointed bristles. The lower cardiac canal opens posteri- 

 orly into the groove upon the anterior surface of the cardio-pyloric 

 valve, while the upper cardiac canal passes beside the valve and opens 

 into the lower canal of the pyloric sac. 



