418 



GOMPARA Tl } r E AX A TOMY 



CHAP. 



to the body) a gill consisting of numerous integumental folds, 

 arranged like the leaves of a book. 



Fin. 284. Limulus polyphemus, young specimen from the ventral side (after Packard). 



The leaf-like feet serve for swimming as well as for breathing. 

 A sternal encloskeleton is present. 



