54 SUMMARY OF CURRENT RESEARCHES RELATING TO 



foreign particles, and which excrete solid and fluid waste products, also 

 allow dissolved carmine to pass through them. Ammoniated carmine is 

 taken up by all phagocytes ; but iron salts do not seem to be so taken up - r 

 for after injections the iron may occur only in traces in the nephridia r 

 but in abundance in the heart-body (Terebellides, Pectinaria). 



In regard to the mechanism of excretion, the author finds that the 

 excretory paiticle forms in the cell-body, and is ejected, probably in 

 company with a little protoplasm, but without the direct participation of 

 the nucleus. In this he agrees with Schoppe, but he finds that the 

 actual expulsion of the excretory particle from the cell is a very compli- 

 cated process, an active process of exchange going on between the cells 

 and the lumen of the nephridial canal. 



The lymphoid organs of Polychaetes and Oligochaetes resemble each 

 other in arising from modified peritoneal epithelium, but otherwise they 

 are not homologous organs. The true chloragogenous cells of Oligo- 

 ehastes appear to be never phagocytes ; but in Travisia and Arenicola 

 among Polychaetes the chloragogenous cells are capable of becoming 

 true wandering phagocytes. The chloragogenous cells of Oligochaetes 

 appear to have their nearest analogue in the cells of the heart-body of 

 Polychaetes ; but the latter may be yet proved to be true phagocytes. 



Note on the Opheliaceae.* — Dr. Maurice Philippson publishes a 

 brief but interesting paper on this aberrant family of Polychaetes. He 

 rejects the hypothesis of Oligochaete affinities, and relates the family 

 to typical Polychaetes through the Ariciidae, to which the Maldanidas- 

 are also related. Within the family of Opheliaceae there is clear evi- 

 dence of the existence of two distinct types of sedentary forms, the one 

 represented by Travisia, the other by Ophelia. Both are independently 

 derived from errant members of the family, and are not related to other 

 sedentary Polychaetes except through errant forms. They thus confirm 

 the theory of the polygenetic origin of the Sedentaria. The author be- 

 lieves that the nervous system is relatively simple and quite typical, 

 being readily reduced to Eacovitza's scheme. The palps are pro!>ably 

 repi-esented by the frontal papilla, the antennae by the sensitive area of 

 the sincipital region, the nuchal organs exist as such ; so that all the 

 typical sense-organs of the cephalic regions are present. 



Regeneration in Polychaetes.f — Herr Eugen Schultz has experi- 

 mented on the regeneration of the posterior end of the body in various 

 worms, chiefly in species of Harmothoe. In regard to the regeneration 

 of the hind-gut there is much difference of opinion among investigators. 

 The present author finds that in the early stages there is considerable 

 variation. In some cases the cut walls of the gut draw together and 

 unite, and the epithelium of the body closes over the united portion. A 

 day or two later the closed gut once more opens, and its walls unite 

 with the epithelium of the body. In other cases the walls of the gut 

 unite directly with the body epithelium, without a preliminary closed 

 stage. As the regeneration of the posterior end of the body proceeds, the 

 mid-gut increases in length and extends into the regenerating area of the 

 body. There is no regeneration of ectodermic hind-gut, but its place is 

 taken by this elongated mid-gut. 



* Zool. Anzeig., xxii. (1899) pp. 417-22. 



t Zeitechr. f. wifs. Zool., lxvi. (1899) pp. G05-24 (2 pis.). 



