Figure 1. 
Figure 2. 
Figure 3. 
Figure 4. 
Figure 5. 
Figure 6. 
Pomona College, Claremont, California 31 
EXPLANATION OF FIGURES 
Embryo of 4. erectus Cole X350. The embryo was taken from the female. 
Larva of A. erectus Cole X350. Just hatched larva with appendages 
straightened. 
Larva taken from the digestive tube of the hydroid. X350. 
Much later larva of 4. erectus taken from the digestive tube of a hydroid. 
This is much less enlarged than the last. X75. 
Free living immature specimen of A. erectus, taken from the surface of a 
mass of hydroids. X35. 
Outline of stages in the early life history of 4. erectus. All figures drawn 
to the same scale X50. (a) Egg, (b) just hatched larva, (c, d, e and f) 
parasitic stages all found at the same time in two polyps. 
