GREA T BRITAIN.- 325 



Northumberland) ; Say - nay (Lancashire) ; Lleppog 

 Welsh). 



Of a shape similar to the lamprey, but rather more com- 

 >ressed posteriorly ; mouth circular ; a single transverse 

 naxillary tooth, having a cusp at either end ; a single 

 ransverse mandibular tooth, with about seven cusps ; small 

 ceth on the disc, and which are few in number ; tongue, 

 vith a broad transverse tooth, having a median cusp ; two 

 )r three teeth on either side of the gullet, which may have 

 ;wo or three cusps ; gills as in the lamprey. Fins. Two 

 lorsals separated by an interspace, the posterior fin con- 



ous with the caudal. Colours. Silvery white, darkest 



g the back. 



r dbits. Yarrell considered that this species is entirely 

 water, as he found no difficulty in obtaining examples 

 any month of the year from the Thames. Very few ascend 

 above the navigation weirs in the Thames or on the Severn, 

 while they deteriorate in value the higher they go. For- 

 merly they reached Montgomeryshire, and are said to have 

 : been taken in the Verniew. In the Severn they commence 

 capturing them near Tewkesbury in September, and the 

 season generally terminates by the end of March ; they sell 

 for about is. 6d. a score, and are largely purchased both 

 for bait and potting. Thompson received one which was 

 captured adhering to a large trout, and continues : " In 

 a large, deep pond, made for gold-fish, at the falls near 

 Belfast, a portion of the surface of which was covered with 

 the leaves of the white water-lily, I observed, on a warm 

 day in summer, an extraordinary appearance, caused; as I 

 believed, by this species. To the under surface of each 

 floating leaf of the plant several (in some instances as many 

 as a dozen) lampreys, about a foot in length, the adult size 

 of this species, attached themselves by the mouth, while 





