63 



my possession. The nerve is connected with the ventral surface of 

 the brain and is ganglionated. 



In other Selachians, — I have found is dissecting the brain 

 of Chimaera monstrosa, a nerve strand on the ventral surface which I 

 believe to be the new nerve, but uot having been able to trace it to 

 its central and peripheral connections, I concede that the presence or 

 absence of the new nerve is undetermined for this form. 



The fissure separating the two divisions of the olfactory nerve is 

 laterally placed in Chimaera, so that the divisions are dorsal and ven- 

 tral in position, instead of median and lateral, as in the other forms 

 described. There are many fine connective tissue fibers between the 

 lobes of the prosencephalon which will make the sure identification 

 of this nerve by dissection a difficult matter in Chimaera. 



In Torpedo, also, I have found in embryos and adults, a strand 

 connected dorsally with the prosencephalon, and running along the 

 tractus which I regard as the new nerve, but, without control of sec- 

 tions for microscopic study, I reserve judgment on the question. 



The observations on Chimaera and Torpedo are recorded here be- 

 cause they are the only selachians I have dissected in which there is 

 any doubt as to the existence of this new nerve. 



The above descriptions make a list of twenty genera (twenty- 

 seven species) in which the nerve has been dissected and found to be 

 ganglionated, and two doubtful genera. (Schluß folgt.) 



Nachdruck verboten. 



Sul sistema arterioso di Selache maxima e di altri Squalidi 



(Acanthias vulgaris, Mustelas vulgaris, Scyllium catulus, S. caiii- 



cula, Squatina vulgaris). 



Nota del Prof. Dav. Carazzi. 



Con 24 figure. 



1. Introduzione, Tecnica e Bibliografia. 



In una Nota pubblicata sul principio di quest' anno (1904) promettevo 

 di tornare, con raaggior larghezza, sul sistema arterioso degli Squalidi, 

 specialmente per cercar di chiarire alcuni punti oscuri e controversi 

 della circolazione ipobranchiale, la quale e poco studiata negli adulti, 

 sconosciuta del tutto dal punto di vista embriologico , e, si puö dire, 

 ignorata dai trattatisti di anatomia comparata. 



