New Species of Edrthivonii. ^ 305 



•end of the gizzard is invaginated, and appears almost urn-shaped, 

 until the front end is pulled out. when it becomes oval. 



The posterior end of the gizzard is between segments six and 

 .seven, and all the septa up to this region are considerably dis- 

 jDlaced, forming angles of about 22.5° ^vith the body wall. 



The anterior end of the gizzard is very changeable, according 

 to the amount of evagination it has undergone. 



Following on from the gizzard is a long, almost straight intes- 

 tine running the length of the body, and opening to the exterior 

 at the posterior end. It presents a bulbous expansion in each seg- 

 ment along its length. (Plate XXVII. Fig. 2.) 



' Nervous System. 

 Ihere is a distinct nerve collar around the oesophageal region 

 in segment two, with a conspicuously swollen dorsal portion slightly 

 pinched in at the median line. On either side of the collar is 

 given off a large nerve, which runs forwards to supply the anterior 

 part of the oesophagus. A smaller branch supplies the crop behind 

 <on each side. After the union of the nerve ring ventrally. the 

 fibres are collected into a very conspicuous cord, which is slightly 

 swollen in each segment. A transverse section of the cord reveals 

 the rather a-typical fact that there is only one large giant fibre 

 present. (Plate XXVII. Fig 3.) (Plate XXX. Fig. 2.) 



Nephridial System. 



From dissection there does not appear to be a nephridial system 

 other than very numerous micronephridia forming a fringed ring 

 around each segment, especially towards the posterior end. 



Microscopic examination of longitudinal sections taken from 

 about the last third of the worm, reveals very peculiar structures, 

 possibly represent a special form of nephridial organ. They are 

 perfectly regular in position, and segnientally arranged. Each is 

 somewhat club-shaped, and attached to the wall of the coelome by 

 a thin stalk. Even under the very high powered objective, there 

 appears to be little structure. The stalk is made up of almost 

 a single chain of nucleated cells, which gradually merge into those 

 of the outer peritoneum. Ihey appear to have no duct, and no 

 passage is visible from them through the muscle layers to the 

 exterior. 



The head portion of the structure has different foi-ms, sometimes 

 l)eing long and regular, with a covering of small nucleated cells. 



