282 LIONEL JAMES PICTON. 



excretion is a possible mode of removal for waste products 

 thrown into the blood by the heart-body^ chloragogen, or other 

 organs connected with the vascular system. 



A remark of Schaeppi's has already been mentioned, that 

 the intra-sinus guanin chloragogen of Ophelia is excreted by 

 being carried through the sinus wall into the peritoneal tissue, 

 clusters of the cells of which eventually become detached and 

 fall into the coelom, and are removed by the nephridia. Quite 

 independently of this, anyone glancing at sections of Audou- 

 inia filigera would suspect some connection between the 

 heart-body and peritoneum. The latter is remarkably thick- 

 ened on the mesenteries which cross the ccelom from the gut 

 and dorsal vessel to the body-wall (fig. 2); its cells are well 

 developed ; their protoplasm is concentrated in their central 

 part, and crowded with yellow or green granulations, and, 

 what is here to the purpose, this tissue is often found lying on 

 the wall of the heart, the inner side of which in many places 

 is connected with the heart-body (fig. 20). Thus it is often 

 found that the peritoneum and heart-body are only separated 

 by the thin muscular wall of the heart ; and that a transfer of 

 granules takes place from one tissue to the other is not im- 

 probable. The granules of the peritoneum, it is true, are not 

 so large as the larger in the heart-body ; but it is reasonable to 

 suppose that the small and disintegrated granules would be 

 the most suitable for excretion. Granular heaps are found 

 floating in the ccelomic fluid, and I have especially noticed 

 them in the anterior part of the animal, — that is to say, in the 

 neighbourhood of the great anterior pair of nephridia. The 

 ccelomic corpuscles also, which are large and amoeboid, fre- 

 quently contain brown granules, though many are occupied by 

 globules of a reddish-brown pigment^ (figs- 21 and 22). These 

 diff'erent places where brown granules are found ^ — the heart- 



' In the season when I examined the ccelomic fluid of Audouiuia it was so 

 filled with genital products that the ccelomic corpuscles were present in 

 relatively very small numbers. 



2 Numerous small, homogeneous, spherical, dull green granules are found 

 also in the gut wall. But they are always on tlie inner side of the nuclei of 



