PETROMYZON BEANCHIALIS. 427 



adult fish. The fishes are not usually met with, but Beneeke states that they 

 may be dug out of the mud every year when an arm o£ the River Alle dries up ; 

 and he believes that their metamorijliosis into Lam perns takes place in the sea. 



River Lampreys are captured in Germany with nets or baskets from 

 December to Easter ; and in the rivers fiowing into the Baltic are taken botli 

 in the spring- and autumn. The Lampern is esteemed as food, and Buckland 

 considered that there is no finer fish. In Germany it is regarded as difficult of 

 digestion, and is usually pickled with spices, potted, smoked, or salted ; and 

 when fresh is stewed or made into pies, as in this country. 



Kessler has described the Petromi/zo)i wagtierl from the Caspian, from 

 which it ascends all rivers which flow into that water. 



Petromyzon branchialis (Linnaeus). — The Pride. 



This Lamprey is rarely more than eight or ten inches long, and about as 

 thick as a swan''s quill. It extends throughout the British Islands, and in the 

 southern part of England is locally known as the Pride. From its habit, 

 first observed by Pennant, of frequenting the mud i-ather than concealing 

 itself under stones. Couch named this little fish the Mud Lamprey. It 

 is distributed throughout the rivers of Europe, from Sweden to Spain, Italy 

 and Russia, and ranges into the Black and Caspian Seas. The same species is 

 found in the western part of North America. It is valued as bait on account 

 of the toughness of its flesh. 



In aspect and character, the Pride, or Sandpiper, closely resembles the Lam- 

 pern (Fig. 209). The head is a little smaller. The external fringe to the oral 

 disc is better developed, but the outer circle of teeth is not developed. The 

 mandibular plate is semicircular as in the Sea Lamprey ; it carries twelve blunt 

 teeth which are equal in size. At the anterior corners of this plate, in the 

 middle of the sides of the mouth, there is a j^late with three teeth in a transverse 

 row (Fig. 210). As in P. Jluriaf'ili.s, there is a smaller plate with two teeth 

 anterior to this, and a plate with one tooth posterior to it, so that the lateral 

 teeth are formed on the same plan as in P . jiuviatUls ; and there are similarly 

 two teeth distant from each other at the anterior corners of the mouth. The 

 teeth are not always uniformly developed. The eyes are smaller than in 

 the Lampern, separated from each other by the diameter of the orbit, and 

 they are a little nearer to the mouth. The gill-apertures are separated from the 

 eye and from each other by distances equal to the diameter of the eye. The 

 single nasal opening is less conspicuous and round. 



The first dorsal fin may or may not be connected with the second dorsal, 



