LOBSTER. 69 



(a) A median ophthalmic artery. 



(b) A pair of antennary arteries, close to (a), 



one on each side. 



(c) Posterior and ventral to (b), a pair of 



hepatic arteries. 

 From the posterior region of the heart : 



(d) A large median superior abdominal artery. 



By longitudinal cuts remove a narrow 

 piece of the abdominal exoskeleton and 

 follow the artery through the abdomen. 



(e) Passing ventrally from the ventral aspect 



of the heart a large median sternal 

 artery : better seen at a later stage. 

 (See below.) 



Diagram of heart and of arteries thus far seen. 

 Folloiv out tliefive arteries from the anterior end 

 of the heart y as far as possible tvitJiout injury to 

 the other organs. 



Out through the anterior arteries, and turning 

 back the heart find the lateral and ventral ostia 

 (B. I. 1. (b), (c)), and the sternal artery (B, I. 

 2. (e)). 



Cut through the sternal artery close to the heart and 

 through the superior abdominal artery and take 

 out the heart. 



Finish diagram of the heart and arteries ! 

 II. Eeproductive System. 



On each side of the heart and partly ventral to it, 

 find: 



