ANATOMY AND PHYSIOLOGY OF ClUTSrACEA 125 



Excretion. — The elimination from the blood of the waste 

 products of tissue changes takes place in a pair of organs Ijang 

 at the base of the antenna, and known 

 as the green glands. Into these organs, 

 which contain coiled tubules, the arteries 

 enter and give up the waste products. 

 These products accumulate in a bladder 

 lying over the gland and from time to 

 time pass out through a duct whose 

 opening may be seen at the base of the 

 great antennae. 



Reproductive Organs. — The sexes 

 are separate in tlie lobster. The eggs 

 are produced in a pair of great sacs 

 which run along on top of the other 

 viscera and are united by a connecting 

 strand (Fig. ] 26) . Each sac has its own 

 duct to the exterior, and this opens at 

 the base of the third pair of walking 

 ajjpendages. The sperm is formed in a 

 pair of sacs resembling the ovary in 

 general shape, but opening by a duct at 

 the base of the last thoracic appendage. 



It ■will be noticed that excretory gland, Fig. 126. — View of ovaries 

 o\nduct, and sperm duct all open out at 

 the base of appendages, and we shall see 

 in studying the structure of ringed worms (" annelids ") that 

 nearly every segment has its duct. Consequentlj' the three 

 paired ducts of the loljster may be regarded as a rudiment 

 of the condition found in ringed worms. 



Musculature of the Lobster. — As the outer cuticula of the 



and oviduct {od) of .'Ameri- 

 can lobster, dorsal part 

 of carapace removed. 



