700 SUMMARY OF CURRENT RESEARCHES RELATING TO 



method of his own, in the demonstration of the neurofibrils in the 

 ganglion-cells of Nereis, Serpula, Lumbricus, and other Annelids. 



Central Nervous System of Annelids.* — J. Krawany has investi- 

 gated this in Eismia foetida. The ventral cord of each side sends out 

 both right and left " effector axones." The sensory centripetal nerve 

 fibres seem to remain on the same side with the exception of those of 

 the superficial plexus. The interstitial cells unite the succeeding seg- 

 ments of the ventral cord of the same side by means of non-crossing 

 axones, and those of the opposite side through crossing axones. In the 

 very dense neurophil of the supra-cesophageal ganglion there end longi- 

 tudinal tracts arising from the ventral cord, which probably consist of 

 axones of interstitial cells and perhaps also of fibres from sensory cells 

 which have reached the brain by centripetal paths. Here also are seen 

 the endings of sensory fibres which enter the brain directly from the 

 periphery. The neurophil is further related to the central ganglionic 

 apparatus of the brain, which consists of a very large number of small 

 cortical cells whose fibres cross in a remarkable way before entering 

 the neurophil. The large connecting cells of the brain appear to play a 

 secondary part. 



Gall-forming Annelid on Ophiuroid.f — H. Ludwig gives a brief 

 note upon an Annelid which is found within gall-like formations upon 

 the arms of the deep-sea Ophiuroid Ophioglypha tumulosa. It is not a 

 Myzostoma, but a well developed Polychsete, to which in the meantime 

 the provisional name of Ophiuricola cynips may be given. 



Modifications of Segmental Organs in Epitokous Polychaets.J — 

 Louis Fage describes the changes in the segmental organs of a number of 

 Polychaets at the time of the reproductive crisis, contrasting different 

 types. In the Lycoridae, where the nephridium is highly specialised, it 

 cannot serve as a genital duct, and it degenerates in the epitokous 

 condition. In other cases, e.g. Cirratulidae and Syllidaj, the simpler 

 nephridium functions as a genital duct. 



Pelagic Sipunculid.§ — P. Mingazzini describes Pelago splicer a aloysii 

 g. et sp. n., a remarkable, spherical, perfectly transparent, pelagic Sipun- 

 culid, which will probably require a new family to itself. It was obtained 

 between New Caledonia and Auckland. 



Vascular System of Oligochaeta. || — H. Freudweiler has made a 

 study of this in various lower forms, e.g. species of Friderieia and other 

 •genera of the Enchytrseidse. The paper contains an account of the gut 

 diverticulum and notes on resorption in the Enchytragidag. The follow- 

 ing points in the vascular system have been made out. Pertaining to 

 the gut sinus are spaces between the gut epithelium and the peritoneum. 

 Spaces between the ccelome sacs right and left, above and below the 

 gut, form the dorsal and ventral vessels. On the dorsal vessel there 



* Arb. Zool. Inst. Wien, xv. (190.-)) pp. 281-316 (5 pis.). 



+ Zool. Anzeig.. xxix. (1905) pp. 397-9. 



\ Comptes Rendus, cx.lL (1905) pp. 61-4. 



§ Atti (Rend.) R. Accad. Lineei, xiv. (1905) pp. 713-20 (2 figs.). 



|| Jenaische Zeitschr. Naturwiss., xxxiii. (1903) pp. 383-422 (2 pis.). 



