32 THE LIFE OF CRUSTACEA 



Lobster turn red when it is boiled ?" is one to which 

 it is not easy to give a simple answer. A chemical 

 change takes place under the influence of heat in the 

 pigment of the shell, which changes it from blue to 

 red ; how slight the change is, is perhaps shown by 

 the fact that occasionally living Lobsters are found of 



a red colour almost as brilliant 



as that which is assumed on 



boiling. 

 The Common Lobster is found 



on the coasts of Western 



FIG. 9-SiDE-viEw OF Europe, from Norway to the 

 ROSTRUM OF (A) * 



COMMON LOBSTER Mediterranean, living in shallow 



(Homarns gammarus) .. . 



AND (B) AMERICAN water, generally a little way 



below low ' tid e mark, wherever 

 a rough, rocky bottom affords 



suitable lurking-places. On the Atlantic coast of 

 North America, Lobsters are also found abundantly 

 in similar situations. These American Lobsters, if 

 examined carefully, will be found to differ from the 

 European kind in certain small details of structure. 

 of which the most conspicuous is the presence, on the 

 under-side of the rostrum, of two spines or teeth. In 

 the European Lobsters the under-side of the rostrum 

 is smooth (Fig. 9). In the nomenclature of technical 

 zoology, these two kinds or species of Lobster are said 

 to constitute (along with a third species found at the 

 Cape of Good Hope) the genus Homarus, the 

 European species being known as Homarus gam- 



