268 LIONEL JAMES PIOTON. 



Beddard (4) supports Horst's view that the organ is hypo- 

 blastic, and suggests comparisons of it with the thyroid and 

 spleen of Mammalia. 



parallel case of the " ciliated pots " of Sipunculus, which collect excretory 

 matter from all sides, this view is surely untenable. The granules must have 

 some other origin ; and their source from cidoragogen, such as that of the 

 heart-body and thoracic sinus, is at any rate not disproved. 



Concei'ning the fate of the rods, the only evidence he adduces is that a 

 collection of them in the body is nowhere found, though clear signs of 

 degeneration are noticeable (p. 298). But since Ed. Meyer has shown, in 

 Terebellidse, that lymph-corpuscles degenerate and are found in the lumen of 

 the nephridium [24, B, p. 648], and as such bodies as the rods could not be 

 carried through the nephridial tubes, to maintain their excretory function it 

 is necessary to suppose that they degenerate. Schaeppi mentions cell-heaps full 

 of granules, and three times the size of the rod-cells, floating in the ccelomic 

 fluid, and occurring also in the cavity of the nephridium itself. He regards 

 them as portions of the chloragogen-bearing peritoneum from around the 

 intestinal sinus, which have fallen off into the body-cavity. Some of them 

 probably bear this explanation ; but in cases, wliicii he overlooks, when they 

 contain rods identical with those of the lymph-corpuscles, it is evident that 

 they are not derived from the peritoneum. In such instances they may con- 

 sist of a Plasmodium of rod-cells, and the granules may be formed by 

 degeneration of the rods. Further — and this can be seen in single corpuscles — 

 the rods appear to undergo a peculiar method of degeneration. Often in 

 larger and older corpuscles the ends of the rods are notched. This notching 

 is such a frequent occurrence that it would appear to have some special 

 significance (fig. 61). Occasionally the part beyond the notch has fallen off^ 

 and may be seen lying in the cell-body (fig. 62). This is perhaps a regular 

 process, and the rod having reached full size continues to grow at the ends 

 into projections which from time to time are detached. The projections are 

 often of a paler colour than the rest of the rod, which may be taken as an 

 indication of recent growth. Degeneration in plasmodia may be the final 

 stage of the rod-cells, when their life-history is complete. 



Corpuscles containing Chitinous Bow-shaped Rods in Noto- 

 mastus profundus (fig. 60). 

 Hitherto the chitinous rods of Ophelia have been unique, no structures 

 resembling them having been found elsewhere among the Annelida. In 

 the hsemolymph of Notomastus profundus, however, I found a cell 

 containing a refriugent bow-shaped rod, which had a strong general resem- 

 blance to the rod-cells of Ophelia. It is not mentioned in the excellent 

 account of the hsemolymph in Eisig's monograph on the Capiteliidse; but 

 the description there deals only with the hsemoiympli in its fresh state, 



