534 MU. A. E. SHIPLEY ON SOME [JuuelO, 



very regularly towards the external end of the cells, and the body 

 of the cell is crowded with granules, in some cases a thin layer of 

 black grannies lies just within the internal ends of the cells 

 (fig. 3). There is no differentiation into parts of this long tube of 

 columnar cells, but the tube is a compressed one, its long axis 

 lying between the two lateral lines; at the sides, as is shown 

 in tig. 1, the lining cells are much natter, and instead of being 

 columnar become cubical. As seems to me not unfrequent in 

 parasitic Nematodes, the intestine contains no trace of food, 

 only the above-mentioned vesicles, and these sometimes in great 

 numbers. 



The body-cavity, which, as Hamann ' has pointed out, caunot be 

 regarded as homologous with the ccelom of, for instance, a 

 Lumbricus, contains a fluid in which numerous small deeply 

 staining granules, probably cells, float. It had coagulated in the 

 anterior end of the body of my specimens in irregular strands and 

 fibrils, which formed a loose network running between the inner 

 ends of the muscles and the outside of the intestine, as shown in 

 tig. 2. At first I was almost inclined to regard this as evidence 

 of the existence of a splanchnic layer of mesoblast, but its true 

 nature soon became apparent. 



The proctodeum is very short and lined by a cuticle, continuous 

 on one side with that of the intestine and on the other with the 

 external cuticle. The line of demarcation is very sharply marked 

 (tig. 4). The columnar epithelium ceases suddenly, and just 

 behind this is a recess or groove, partly formed by the increase 

 at this spot of the thickness of the wall of the tube by a muscle 

 which probably acts as a sphincter. 



In this region of the body the distribution of the nerves has 

 been admirably described by Hesse for Ascaris megdlocephala^ and 

 although the preservation of my material did not permit me to 

 follow out all finer details of this system, 1 have no reason to 

 doubt the correctness of his observations. 



Immediately behind, or at about the same level as the sphincter 

 muscle, lie three problematical bodies, which are very conspicuous 

 in both longitudinal and transverse sections, yet which have as a 

 rule escaped the notice of workers at this group. Hesse mentions 

 these structures and calls them " Gewebepolstern," which does not 

 help us much ; he suggests they may have an excretory function. 

 It is of course not impossible that these bodies may serve as a 

 place where the waste nitrogenous material is stored up within t he 

 body of the animal, such as is found in some Ascidians : but there 

 is no evidence of this, and the canals in the lateral line, which are 

 usually regarded as excretory, have a quite adequate opening to 

 the exterior. 



At first sight these " Gewebepolstern " might easily be taken 

 for three gigantic cells encircling the rectum close behind the level 

 where the columnar cells of the intestine cease and the rectum 



1 " Zur Entstelmng des Exkretiousorganes der Seitenlinic-n und der Leibes- 

 hukle der Neniatodeii," Ceutralbl. fur Bakteriologie, Bd xi. 18'J-. 



