No. 4-] NORTH-AMERICAN ECHIURIDS. 173 



The foregut is very short, and contains a pharynx and 

 oesophagus which are often bright orange in color like the 

 inside of the proboscis. The remainder of the foregut is usu- 

 ally larger in diameter and has been called the crop. The 

 midgut constitutes the bulk of the alimentary canal and is dis- 

 tinguished by a groove lined with vibratile cilia which runs 

 along its dorsal side. Opening into this groove at either end 

 is a collateral intestine, much smaller in diameter than the mid- 

 gut and seemingly analogous to that in echinoderms. 



The hindgut is somewhat larger than the midgut and forms 

 near the anus a cloaca into which open two anal vesicles, one 

 on either side. These are quite long, simple sacs, light brown 

 in color, which vary greatly in length in different individuals 

 (40-70 mm.). They open into the body cavity by ciliated fun- 

 nels, which are most numerous near the base of the sacs, and 

 one of which is terminal. 



Both males and females have two pairs of nephridia, which 

 open on the ventral surface on either side of and close to the 

 nerve cord. The mouths of these nephridia are raised into 

 large papillae on the external surface of the body, and can be 

 plainly seen, the anterior pair just behind the ventral setae, 

 and the second pair 5 or 6 mm. farther back. 



At the base of each nephridium on the inner side is a cili- 

 ated funnel opening into the body cavity, through which the 

 sexual products enter the nephridium when sufficiently ripe. 



They are then discharged through the external papillae into 

 the water. When free from eggs the nephridia are 15-20 mm. 

 long and spindle-shaped, with a diameter of 3-5 mm. at the 

 center. Probably when filled with ripe eggs or sperm they 

 increase proportionately in size. 



The Sexual Products are doubtless formed, as stated by 

 Greef, from small cells near the posterior end of the ventral 

 nerve cord, which are covered with peritoneum. But repro- 

 duction certainly does not take place in this locality (Casco 

 Bay) in July and August, as well as in midwinter, viz., it does 

 not occur twice a year. All my specimens were secured in 

 June to August, and not one of them contained ripe sperms or 



eggs. 



