CLASS CRUSTACEA. 



33 



and are movably jointed or "articulated" to the body. 

 Hence the Lobster is emphatically what is called an 

 "Articulate" animal (Latin, a7'tiadatus, jointed). 



It remains very briefly to consider the more important 

 points in the internal anatomy of the Lobster. The 

 mouth is placed on the under surface of the head, and in 

 addition to the numerous jaws already alluded to, it is 

 further provided with an upper and lower lip, both of a 

 shelly nature. The mouth leads by a gullet to a globular 

 stomach, from which an intestine proceeds, to terminate 

 by a distinct vent at the base of the last segment of the 

 body ; and there is a well-develojied liver. 



The heart (fig. 14, h) is placed upon the back, and 

 drives the pure blood, which has passed through the gills, 

 to all parts of the body. The breathing-organs {b b) are 

 adapted for breathing air dissolved in water, and are 

 therefore genuine "gills." They are in the form of 

 pyramidal bodies, which are attached to the bases of the 



Fig. 14.— Diagram to show the position of the internal organs of tha Lobster 

 as they would be seen if the animal were cut across behind the head. 

 h Heart ; 6 b Gills (the vessels containing pure or arterial blood are left 

 light, those containing venous or impure blood are dark); i Intestine; 

 n Nervous system. 



legs, and are concealed from view beneath the sides of 

 the great shield which covers the head and thorax. Owing 



