458 PETROMYZID.E. 



This species was named by Blocli after his friend Planer, 

 a professor at Erfort, who sent him specimens ; but if BlocVs 

 species be the same as our British fish, his figure is excep- 

 tionable. This Lampern appears to be well known to M. 

 Nilsson, who includes it in his Prodromus of the Fishes of 

 Scandinavia, and says it is an inhabitant of almost all the 

 brooks and rivers of Sweden, and that it spawns in April or 

 May. M. Nilsson gives to this fish the length of six inches 

 only : it appears therefore that this species, like P. marinus 

 and P.fiuviatilis, does not acquire in high northern regions 

 the size of our specimens in this country. 



When compared with P. Jluviatilis, Planer"'s Lampern has 

 the orifice on the forehead, the eye, and the first of the bran- 

 chial apertures, much nearer the anterior edge of the lip than 

 in the other species ; the lip broad and fringed, and the dis- 

 position of the teeth as shown in the additional figure of the 

 mouth only : the first dorsal fin begins about the middle of 

 the whole length of the fish, and is in close contact with the 

 second dorsal fin, which in its base is as long again as the 

 first : the tail is furnished with an extension of membrane 

 above and below, forming a caudal fin ; and a narrow slip 

 passing forwards towards the anal sheath, forms a rudimen- 

 tary anal fin. 



In its colours this species agrees with the common Lam- 

 pern, being dusky blue on the back and sides, passing into 

 silvery white on the belly, the fins having a brown tint. 



In its habits, Planer's Lampern so closely resembles the 

 common Lampern, as frequently, no doubt, to have been 

 mistaken for it. Both may go to the salt or brackish water 

 from that part of a river within the influence of the tide. 



