1883.] PROF. HUXLKY ON THE OVIDUCTS OF OSMERUS. 



137 



the same series ; that is to say, the abortion of the oviducts, com- 

 menced in Osmerus, is completed in Salmo ; and all that remains of 

 the primitive arrangement is the fold described by Rathke and the 

 so-called " abdominal pore," which, it will be observed, is the homo- 

 logue of half of the urinogeuital opening of the Ganoids, and has 



Fig. 2. 



ov. I. 



od.a 



tr.& 



The left ovary and oviduct of Amia culva, half natural size. 

 ov. I, left ovary ; m.o. I, left mesoarium ; od. I, left oviduct; od. a, opening of the 

 oviduct into the " bladder." 



nothing to do with the " abdominal pores " of these fish and of the 

 Selachians. 



As is well known, Lepidosteus presents an example of a Ganoid 

 with oviducts like those of the higher Teleostei ; in Osmerus, on the 

 other hand, we have a Teleosteau with oviducts like those of the 

 ordinary Ganoidei. It is tolerably obvious, therefore, taht the cha- 



10* 



