TEANSVEESE SECTIONS 



195- 



The section lies behind the atrial cavity, which is 

 therefore entirely absent. 



The skin and the skeletal, -muscular, and nervous 

 systems are practically the same as in B, except that 

 the ventral muscles are absent. 



Pio. 44. — AmpWoxus lanceolatus. Transverse section of an adult 

 specimen, passing through the anus. (a. m. m.) 



A, dorsal fin. B, spinal cord. C, uotocliord. D, connective-tissue slieath 

 of notoohord. I, ventral fin. K, intestine. K', anus. O, ooelom. Q, dorsal 

 aorta. 



2. The intestine lies below the notochord, and the anus is 



on the left side of the ventral fin. 

 S. The ooelom is a space surrounding the dorsal and lateral 



surfaces of the intestine. 

 4. The dorsal aorta is a median vessel in the connective 



tissue below the notochord. 



o 2 



