ANATOMY OF A MACTRA. 



Fig. 88. ANATOMY OF A. MACTRA. 



Explanation of Fig. 88. Anatomy of a rnactra ; one valve of the shell, 

 the corresponding half of the mantle and the branchiae have been removed 

 on the left side : c. the shell ; wi. the mantle ; ma. the anterior muscle ; 

 mp. the posterior muscle ; b. the mouth; t. the tentacle; e. the sto- 

 mach; as. appendix of the stomach ; i. the intestines ; /. the liver ; p. 

 the foot ; co. the heart traversed by the rectum (r) ; ts. the superior tube 

 into which the anus (a) opens ; ti. the inferior or respiratory tube ; br. the 

 branchiae of the right side ; ga. the anterior ganglia ; na. nerves arising 

 from them; ng. inter-ganglionic nerves; gp. posterior ganglia; np~ 

 nerves arising from them and distributed to the mantle. 



