28 ART. 8. 1. IK EDA : THREE NEW AND 



collateral intestine and which runs down nearly as far backwards 

 as the junction point of the anal glands. The part in question 

 of the intestine lies ventral to the windings of the first part and 

 takes at first an anteriorly directed course up to about the middle 

 of the body ; it then makes a sharp bend, thence to run back- 

 wards down to the anus at the posterior body-end. The terminal 

 part of the intestine which may be called the rectum, is very 

 short. 



The alimentary canal in its entire length, excepting the 

 pharynx and the " typhlosohle " bearing portion of the œso- 

 phagus, is always filled with fœces which are in the shape of 

 small rods. 



Having given above the gross features of the alimentary 

 canal, I will now pass over to its microscopic structure. In this 

 respect the present species presents not a few j)oints of peculiarity. 

 For the sake of comparison, I have studied histologically the 

 same organ-system of Echiurus unicmctus, a species which more- 

 over was thoroughly described by Selenka ('85) and Alice 

 Embleton ('00) ; and I have found that, while that species 

 presents an essential agreement with other previously known 

 Echiuroids in the anatomy as well as the histology of the digestive 

 system, the present species shows no small degree of deviation in 

 those respects, especially as regards the microscopic structure of 

 the foregut and of the anterior portion of the intestine. 



The wall of the pharynx consists of four layers, viz., the 

 mucous membrane, the muscular layer, the trabecular layer and 

 the peritoneum. See PL III., fig. 32, which represents a part 

 of a cross-section through the pharynx and the wing-like lateral 

 mesenteries {w.m.). 



