CHORDATA 425 
Sub-class I. ENTEROPNEUSTA. 
CHARACTERISTICS.—Soft worm-like animals with ciliated ectoderm. 
The trunk, succeeding the collar, is long and somewhat 
flattened. The alimentary canal is straight, and the anus 
opens at the end of the trunk. There are numerous gill- 
slits, which inerease in number during life. 
There are several species of alanoglossus described. 
Fic. 244,—View of an adult male Balanoglossus Kowalevskit. Magnified one and a 
half times. After Bateson. 
1. Proboscis. 6. Mouth. 
2. Collar, 7. Gill-slits. 
3. Trunk. 8. Lateral edge of the body where it 
4. Region of Testes. becomes flattened. 
5. Tail. 9. Anus. 
B. clavigerus and minutus are found in the Bay of Naples, 
B. salmoneus and robinii off the coast of Brittany. The 
