66 ILUNOIS BIOLOGICAL MONOGRAPHS (186 



cavities present are not true coelomic cavities, but remnants of the blas- 

 tocoel or primary body cavity. The intestine adheres to one side of the 

 cavity, but is not covered by the peritoneal lining. In the early stages 

 the gonads also are not covered by parenchyma. 



The two species investigated differ widely in the distribution of the 

 mesenchyme in the female. In Gordius robustus the mesenchyme does not 

 surround the ovaries while in Paragordius varius it completely surrounds 

 them. 



Vejdovsky was unfortunate in his investigations in that the earliest 

 stages at his disposal were those in which the mesenchyme had just com- 

 pleted the formation of the lining of the muscles and the covering for the 

 gonads. At that stage it appears more like true epithelium than at any 

 other. In his specimens the appearance was even more that of true epithe- 

 lium because the looser mesenchyme cells were not preserved. 



No true circulatory system is present, but the body cavities may be 

 regarded as chambers that aid in the distribution of liquids in the body. 



No trace of a special organ for excretion is present. Montgomery 

 found in one female an elongated organ passing along the dorsal side of 

 the anterior part of the intestine and at intervals giving off branches. He 

 regarded this as the vestige of an excretory organ and described and figured 

 it in detail. Indeed he described it so well that his error in interpretation 

 is easily detected. The structure was nothing more than the mycelium 

 of a fungus, such as are often found in older specimens. Montgomery 

 himself states that "it is most remarkable that this organ appears to 

 possess no nuclei of its own. Small deep-staining nuclei are found in it 

 (about 29 in number) , but from the close resemblance of these to the nuclei 

 of the parasitic organisms found in the lumen of the medio-ventral canal, 

 they certainly belong to such parasites which have penetrated the walls of 

 the organ." 



Reproductive organs. The origin of the germ cells must still remain a 

 mystery. That the bodies found by Schepotieff in the larval stage at the 

 sides of the intestine are really the primordial germ cells is very doubtful 

 both from the appearance of similar bodies in other species and from his 

 own description. In the larvae of Paragordius varius examined by me 

 similar bodies were present. Montgomery figures two bodies, a smaller one 

 anterior and a larger one posterior, but states that more may be present. 

 In the specimens examined by me there were present invariably the larger 

 posterior body, which undoubtedly is a part of the intestine filled with a 

 substance of nearly homogeneous nature, and two smaller, spherical bodies 

 with deeply staining centers, attached to the antero-lateral edges of the 

 larger body. Montgomery regards the substance includecf in the bodies as 

 excretory in nature. In Gordius robustus, where two bodies appear that 

 answer more closely to the descriptions and figures of Montgomery, these 



