OF THE BRITISH ISLANDS. 121 



bait to the Dutch fishermen. Twelve hundred thousand 

 represents the number recorded as having been thus sent 

 away from this river alone in a single year. The Sand-pride 

 or Mud Lamprey (P. branchialis), No. 230, is a yet smaller 

 fish about the length of a moderate-sized worm, and not 

 thicker than a pipe stem, that is likewise an exclusively 

 fiuviatile form, addicted to burying itself deeply among the 

 mud and ooze of our large rivers, and spawning like its 

 congeners during the spring months of the year. The last of 

 the Lamprey types is the Glutinous Hag or Borer {Myxine 

 glutinosa), No. 231, having its mouth furnished with eight 

 cirrhose processes, and so constituted that it can bore its 

 way into the bodies of dead, and some say living fish, upon 

 whose flesh it then feeds, leaving nothing but the bones and 

 skin intact. An example of this species, which is not un- 

 frequently taken on the Eastern counties coast-line, is among 

 the desiderata of the South Kensington Collection. 



ORDER V.— LANCELETS (Pharyngobranchii). 



Primitive spinal axis or notochord extending to the 

 anterior end of the body ; no limbs, skull, brains, auditory, 

 or renal organs, as in the higher Vertebrata ; the heart a 

 simple tube ; the liver succular. 



But a single type, the Lancelet or Amphioxus (Amphioxus 

 lanceolatus), No. 232, represents this lowest organised, but 

 at the same time exceedingly interesting and important, 

 order of the Vertebrata. It is a compressed lanceolate form 

 not exceeding two to three inches in length, perfectly trans- 

 parent when living, possessing as shown in the accompanying 

 figure no distinct head, eyes, limbs, dermal covering, or other 



