66 



LOWER VERTEBRAtES. 



the same way to fishes, and scrape off the flesh with then- rasp-like teeth. The portions 

 thus torn off, as well as the blood that flows, forms the larger part of their food. 

 When thus attached they can still breathe, for they draw in the water through the gill 

 slits and then force it out again in the same way. 



Lampreys are very differently estimated as food in different places, even within 

 the same country. The ancient Romans prized them highly, and to-day they are held 

 in high esteem in various parts of the Continent and in England, but in Scotland they 

 are despised. In America the same difference appears. In Hartford, Conn., and its 

 vicinity large numbers of the sea lamprey (P. marinus) are taken for the table every 



Fig. 5i. — Petrormjzon marinas, sea lamprey (above); Lampetra fluviatUis, lampern (middle); 

 P. branchialis, pride (below). 



spring, but in most other parts of the country they are disregarded. This species 

 attains a length of about three feet, and is the lamprey proper. Z. fluviatUis, l^a 

 river lamprey or lampern, is smaller. Still smaller is the pride, or sand-piper, P. bran- 

 chialis. 



The lampreys undergo a metamorphosis in their development. The genital pro- 

 ducts, after ripening in their respective organs, escape into the general body cavity, 

 and then pass out through a genital pore into the sea. Their development has been 

 studied by the late Dr. Calberla of Germany, and Dr. W. B. Scott of Princeton. The 

 earlier stages resemble in many respects those of the Batrachia, but later the embryo 

 takes on its peculiar character and develops into a larval form, long regarded as a 



