136 



tract, since it lies under the outer coat of the latter. Immediately 

 anterior to the third pair of septal glands it gives rise to two irregular 

 branching outgrowths, one on the right and one on the left side, which 

 escape from the enclosing sheath of the digestive tract and extend 

 freely into the coelom, showing a tendency to lie in close proximity 

 to the dorsal blood-vessel. The main part of the dorsal peptonephrid- 

 ium continues caudad, maintaining its intimate relation with the 

 digestive tract, and ends just anterior to the origin of the intestinal 

 diverticula. The ventral peptonephridium is also composed of two 

 parts, one ental and the other ectal. The ectal part resembles the 

 corresponding dorsal one in structure and mass, but differs in shape 

 and distribution. Just beyond its origin it enlarges and extends into 

 the body cavity. It is composed of two parts, one of which extends 

 cephalad for a distance of about half a somite, forming about four 

 fifths of the bulk of the structure, whereas the other extends caudad 

 for a short distance. The former is unbranched. The ental part re- 

 sembles the corresponding dorsal one in structure and in its relation 

 to the digestive tract. Just anterior to the third pair of septal glands 

 it gives off right and left branches w^hich project freely into the body 

 cavity, extending dorsad around the alimentary canal. These branches 

 are in close proximity to the corresponding ones of the dorsal pep- 

 tonephridium but do not unite with them. The main part of the ven- 

 tral peptonephridium continues caudad, maintaining its intimate rela- 

 tion to the digestive tract up to a point just anterior to the intestinal 

 diverticula, where it again gives rise to right and left branches which 

 extend into the ccelom. These branches are similar to the correspond- 

 ing anterior ones except that they are not so extensive. The main 

 part of the gland, which is longer than the dorsal peptonephridium, 

 ends just anterior to the origin of the intestinal diverticula. All of 

 the various parts of the peptonephridia have essentially the same 

 structure. They are rather thick-walled, tubular, and conspicuously 

 nucleated. The peculiarly thickened portions at the origin of the 

 glands vary from the other parts in staining capacity, and to some 

 extent recall the peptonephridia in H. leptodera Vejd. as figured by 

 Vejdovsky ('79, Taf. X, Fig. 2). 



Taste Organs. — A pair of these organs arise from the floor of the 

 buccal cavity, one on each side of the median line, and extend out into 

 the lumen. They are about 0.057 ^''i''^- long"- The basal part of each 

 is somewhat constricted, forming a sort of pedicel, and the remainder 

 is spindle-shaped, thick in the middle and tapering to a point at the 

 extremity. The body of each of these organs is composed of elon- 

 gated, nucleated cells which resemble the other epithelial cells of the 



