244 SUMMARY OF CURRENT RESEARCHES RELATING TO 



this kind arc formed during tlio course of development, but arc sub- 

 sequently replaced by widc-moutbcd vibratilo funucla. Those are 

 not the homologues of the vibratilc cells, but should rather be con- 

 sidered as neomorphs which originate in the blastema, distinct in 

 their origin from those of the segmental organs. The longitudinal 

 canals of the Platyhelmiuthes recur as ephemeral organs of transition 

 in the ontogeny of Polygordius ; in Lankc conchilega they persist even 

 up to the adult stage. In the Rotifera it is the longitudinal canals 

 and vibratilc cells of the Platyhelminthes that are preserved, but the 

 segmental orifices are lest. 



Sclerostoma boularti.* — P. Megnin gives an account of a new 

 Strongyle found by M. Boulart in the trachea of Casiiarins galeatus ; 

 in many points it resembles Si/ngamiis trachealis, but differs from it 

 in that the sexes are not permanently united, as they are always 

 found to be in the single species of Syngamus which is known to us. 

 It becomes, indeed, doubtful whether the genus Syngamus ought to bo 

 retained at all, and not merged with Sclerostoma, as was done by 

 Diesing. 



After a few notes on the anatomical characters of the now species, 

 Megnin remarks that, if individuals are not ordinarily more numerous 

 than they were in the cassowary dissected, where there were only six 

 pairs, the most they can do is to produce some cough ; in younger 

 specimens a smaller number would, with the narrower trachea, produce 

 suffocation than in adult forms, but evjn in that case some fifty 

 would be required to block the passage of the trachea. At the same 

 time it is to be remembered that the endoi^arasitic nematoids are 

 blood-suckers, so that they must produce a certain amount of ana)mia, 

 the significance of which must not be left out of consideration. 



Excretory Organs of Nemertines.f— A. W. HUbrecht has dis- 

 covered in a species of Pala3oncmertino that the excretory system 

 communicates on both sides with the lateral blood-vessels by several 

 apertures ; the excretoi'y canals instead of being as in the Trematodea 

 and Hirudinea, rows of perforated cells, are composed of a cylindrical 

 mass of cells surrounding a central lumen which in most cases is 

 richly ciliated. Dr. Hiibrecht also records the discovery by Oudemans 

 of numerous external apertures of the ne2)hridia in Linens, Amphiporue, 

 &c. 



Nervous System of Tsenia.J — J. Niemicc, after an expression of 

 admiration for the investigations of Blanchard on the nervous system 

 of the Cestoda, states that he has made investigations on Tcenia 

 ccenurus, T. elliptlca, T. serrata, and T. mediocaneUata, by means of 

 sections. Immediately below the internal angle of the hooks of the 

 rostrum (where such are present) there is a nervous ring which 

 gives off superiorly a series of branches to the musculature of the 

 hooks ; inferiorly, the same ring gives off eight nerves, at the base of 

 which is a slight swelling formed by ganglionic cells ; these go by 



* Journ. de I'Anat. et Physiol., xx. (1884) pp. 455-61 (1 pi.), 

 t Zool. Anzeig., viii. (1885) pp. 51-3. 

 j Comptes Rendus, c. (1885) pp. 385-7. 



