604 SUMMARY OF CURRENT RESEARCHES RELATING TO 



to be well established as applied to the development of the urinary 

 apparatus of the Platodes and Eotifera, for all Annelids, including 

 the Gephyrea, for the Bryozoa, Mollusca, and Brachiopoda; even, 

 too, for the Nematodes and Cephalotricha, and, perhaps, also for the 

 Arthropoda." 



The author then proceeds to his ideas on the body-cavity, and 

 enters into an elaborate account of the speculations of Eay-Lankester 

 (see next note), which he hardly represents accurately. He concludes 

 that the system of the canals of the excretory apparatus of the 

 Trematoda and Cestoda does not constitute a true blood-lymph system 

 at all, but that it is an apparatus with the same definite objects as the 

 segmental organs of the Annelids. On the other hand, the blood- 

 lymph system of these worms is solely formed by intercellular spaces, 

 of lacunae, and of interstitial plasmatic lacunae. 



Ccelom and Nephridia of Platyhelmia.* — Professor Eay-Lan- 

 kester, in reference to the notice as to his views which M. Fraipont 

 has made in the previous paper, remarks that Haeckel had criticized 

 the doctrine that j^art of the fine canal system in the Platyhelmia 

 represented the ccelom of Ccelomata, by justly urging that " we did 

 not possess any knowledge of the development of the canal system 

 in Platyhelmia which warranted the assumption that any part of it 

 was the representative of the coelom of other animals." The dis- 

 covery by Biitschli, and the extension of his observations by M. 

 Fraipont, as to the existence of the terminal ciliated bodies of the 

 nephridia, are of importance as enabling us now to say, " Here 

 nepbridium ends, and here coelom begins." Professor Lankester points 

 out that what he has believed to be the case — viz. that the ultimate 

 ramifications of the canal-system were intercellular, and, like the 

 sinus-system of a mollusc, equivalent to a coelom, is just what 

 Biitschli and Fraipont have proved to be the fact. 



Anatomy of Distomum clavatum.-|- — Dr. E. Jourdan has a note 

 on this form, which is remarkable among its allies from the fact that 

 it lives freely and is not parasitic ; and the chief aim of this notice is 

 to demonstrate that, notwithstanding the doubts of Dujardin, this 

 form is truly a Trematode. The essential characters of the species 

 are the size of the abdominal sucker, the deep transverse folds which 

 are developed on the posterior region, and the canal-like depression 

 which intervenes between the buccal and the abdominal sucker. 

 These specific characteristics distinguish as much the free-living forms 

 as those which were found in the intestine of the tunny. The author 

 enters into a short account of the different organs, the characters of 

 which appear to justify him in his belief as to the Trematode affinities 

 of this sometimes free form. 



Development of Tricuspidaria nodulosa.J — The epidemic among 

 the perches of the Seine has given M. P. Megnin an opportunity of 

 studying this parasite. The livers of all the perch examined were 



* Zool. Anzeig., iv. (1881) i^p. 308-10. 



t Rev. Sei. Nat, ii. (1881) pp. 438-9 (2 pis.). 



X Comptes Rendus, xcii. (1881) pp. 294-6. 



