202 Prof. C. Gegeubaur on Trachelius ovum. 



the body,. and become amalgamated with the wall of the body, 

 which is considerably thickened here and there. These trabe- 

 culse are contractile. In the principal mass of the structure 

 originating from the mouth, and which has been compared to 

 an "intestine/' I not unfrequently found balls of food, and 

 indeed always in the posterior and never in the anterior half of 

 the body, the direction of the pouch-like cleft being downwards. 

 Sometimes the balls of food were accumulated in the obtuse ex- 

 tremity of the body. They appear also to be capable of passing 

 through thin trabeculse, for not unfrequently one of these enclosed 

 a ball, often of considerable size, about the middle of its length. 



I have given the name of " intestine'^ to the branching sub- 

 stance passing through the body from the mouth, merely because 

 the food is always enclosed in it, but no further idea is to be 

 attached to this term. There exists no essential difference be- 

 tween it and the substance of the walls of the body. 



In the substance enclosing the balls of food, however, there 

 lies an organ, which, in accordance with Siebold's views, must 

 be designated the " nucleus." It is a sharply circumscribed, 

 band-like structure, somewhat inflated at both ends, and com- 

 posed of closely appressed globules. One end is usually directed 

 forwards, the other backwards. Is this Ehrenberg's band- like 

 gland ? All individuals presented this organ ; the form, size and 

 position certainly varied, but it always lay with its central part 

 close to the buccal cleft, which passed over it with its csecal process. 



The buccal cleft, that is to say, what I regard as such, is not, 

 however, the only opening on the body. A far smaller one lies 

 further in front, a little below the moveable " proboscis ;" at 

 that point also the v»'all of the body is more strongly thickened, 

 and produced into a trabecula, which is either united with the 

 rest of the trabecular system only by a very thin branch, or 

 inserted with its extremity at some point in the opposite wall. 

 I always found the opening to be of the same diameter; the 

 cilia surrounding it strike towards it. It leads into a tube which 

 is at first somewhat dilated and provided with firm walls, then 

 narrowed in the form of a funnel, but destitute of cilia through- 

 out ; it frequently presents delicate longitudinal folds, and is 

 continued into the above-mentioned trabecula. 



This aperture with its continuation has nothing except its 

 position in common with the orifice described by Ehrenberg in 

 Trachelius ovum. I have observed a great many individuals for 

 a long time under the microscope, but have never seen a dilata- 

 tion of the aperture; on the contrary, I have seen, although 

 rarely, a dilatation of the funnel-shaped extremity of the canal, 

 so that the lumen equalled the external aperture. At the same 

 time I also think I have seen an opening at the end of the canal ; 



