8 ART. 8. T. IKEDA : THREE NEW AND 



The above trabecular layer corresponds, in joosition at least, 

 to the parenchymatous tissue of the authors on Bonellian males. 

 That tissue has been sjenerally considered to consist of an ao-o-rega- 

 tion of stellate cells, a view which I am quite at loss to reconcile 

 with what I have seen and described above. Some writers — 

 amongst them Vejdovsky ('78) for one — have stated that blood- 

 corpuscles and spermatozoa occur in the tissue-spaces of the 

 parenchyma and that they both are generated from that tissue. 

 Now, in the male of Bonellia miyajimai I can say with certainty 

 that free cells never occur in the layer and that the male sexual 

 colls originate, as will be shown further on, from a source ap- 

 parently quite independent of the tissue in question. 



The fourth layer of the body-wall is offered by the sub- 

 peritoneal musculature, consisting of fine muscular fibers that run 

 in oblique directions just outside of, and in direct contact with, 

 the peritoneum. Tlie layer is in general exceedingly thin and 

 not always easily distinguishable. Only along the ventral median 

 line of the body-cavity, it presents a not inconsiderable thickness. 

 In this position, it can be plainly made out that there exist in 

 the layer two intersecting systems of obliquely running muscular 

 fibers {o.m., fig. 9, PI. II.). In each system the fibers are 

 arranged in a single layer, nearly parallel with one another and 

 in short but moderately uniform distances. Their course strikes 

 an aiiglo of approximately 40° in relation to the longitudinal 

 body-axis. 



It lias been stated by some investigators of Bonellia that a 

 peritoneal layer does not exist in the male. Contrary to this 

 statement, I find the inner surface of the body-wall lined with 

 a thin epithelium which might without impr023riety be called the 

 peritoneum {jw-, figs. 11 and 12). As seen in sections, it consists 



