46 



GENERAL ZOOLOGY 



Inside the body there was a tubular digestive system 



extending from mouth to anus. 

 This began as a gullet or 

 esophagus, was enlarged a little 

 behind the head to form a 

 stomach, and continued 

 through the rest of the body 

 as a straight intestine. Above 

 the alimentary canal there was 

 a long tubular heart which 

 received blood through paired 

 openings in each metamere and 

 pumped it forward. The ner- 

 vous system consisted of a 

 " brain" (the supraesophageal 

 ganglion), dorsal to the esopha- 

 gus, and a chain of metameric 

 masses of nerve cells, or gang- 

 lia, on the ventral side of the 

 alimentary canal. There were 

 nerves from the ventral chain 

 of ganglia to each of the ap- 

 pendages and to the internal 

 organs; branches from the 

 brain supplied the optic (or 

 eye) ganglion, the antennae, 

 and some of the mouth parts. 

 There was a pair of kidneys 

 in each metamere which opened 

 to the outside through pores 

 in the exoskeleton. Near the 

 posterior end of the body were 

 a pair of tubes (the gonads, or 

 sex glands), which shed egg- 

 or sperm-cells through the 

 anus. 



From such an ancestor the five existing classes of arthro- 



