LOBSTERS: The ovaries of the female lobster are located in the cephalothorax, and extend through the abdomen. In figure A, paired oviducts emerge just below the heart and run downward toward the base of the third pair of thoracic legs. There they meet the seminal receptacle, a bluish structure extending from the third walking legs to the fourth.

In figure B, the testes of the male lobster are variable in shape and may be either longitudinally paired or H-shaped. Similar to the female oviducts, in the male, paired ducts, called the vas deferentia, emerge just below the heart and run downward toward the of the fifth walking legs. Along this course, they become thicker and glandular, and then they become narrow and thin-walled to form the duct. The thick, glandular portion of the vas deferentia secrete a gelatinous matrix over the sperm to form dense packets of sperm called spermatophores.


SHRIMPS: Shrimps are protandric hermaphrodites, maturing first as males before changing into females. At 2 1/2 years of age, shrimp mature as males and fertilize older females in offshore waters. After breeding, the males change into females. Adult females move into inshore waters to spawn.