524 TEN YEAES IN SWEDEN. 



8. truttulttj Nilss., sterile form. Sw. liafs forell, gra lax, 

 Sorting. Fin. taimar. 



" Professor Nilsson," he remarks " has made of this fish 

 not less than three distinct species,, viz. : 



" S. trutta, L. The young full grown fish in winter 

 and spring during its residence in the sea. 



" S. ocla. The same fish ready to spawn in rivers, 

 and most probably the female fish directly after spawning. 



" S. eriox. (Grey or bull trout, Yarr). A very old 

 fish, which has lost its teeth on the hinder part of the vomer." 



Professor Nilsson's statement that the ocla is met with 

 in the large Scandinavian lakes, has arisen from a confusion 

 with the trutta lacustris, Sieb. (S. salar, var. lacustris 

 Hard., a description of which will be found below). In 

 Finland they take this S. trutta, L. mostly in the northern 

 Osterhottens rivers, where they are called taimen, but they 

 are also found in the Grulf of Finland and the Polar Sea. 

 It is undeniable that the S. spurius, Pall., belongs to this 

 species. 



"According also to Widigren the "borting" or 8. 

 trutta, and the S. eriox are the same fish at different ages, 

 for he says there are no specific characters which" can dis- 

 tinguish the S. eriox from very old individuals of the 

 S. trutta. 



" S. truttula, Miss., Prod., of which through the kind- 

 ness of Dr. Widigren, I have received specimens from Ide 

 Fjord, in Bohus Land, is without doubt a sterile form of 

 the S. trutta, as is the 8. Schiejfermulleri, Bloch. (Wetterns 

 silfver lax), only a sterile form of the trutta lacustris, 

 Sieb." This I doubt. 



The investigation of this subject of sterility in the 

 genus salmo is interesting. That there may be sterile 

 forms of both the Wetterns and Wenerns silfver lax which 

 I believe are precisely the same fish, I do not deny, but 

 they are certainly very rare in the Wener, where we have 

 two clearly distinct species of lake trout, which never by 

 any chance appear to breed together, and both of which 

 are taken in our lake in the autumn, full of roe and milt. 



