168 
IOWA ACADEMY OF SCIENCES. 
Summary of Results . — An examination of the chart 
reveals the following facts: 
1. There was an equal number of injuries to the right 
and left antennae of the first order in the males, while in 
the females none were injured. 
2. The injuries to the right antennae of the second 
order in the males were 50 per cent greater than those of 
the left, there being an equal number of injuries in the 
females. 
8. The injuries to the right clielipeds were 50 per cent 
greater than those of the left in the males, while in the 
females there were the same number of injuries in the 
right and the left. 
4. The proportion of the injuries to the right and left 
walking legs in the males was as 6 to 1, in the females as 
5 to 8. 
5. With the single exception of a male charted as num- 
ber 8, none of the pleopods were wanting in any of the 
specimens. 
6. Making the total number of individuals the basis of 
computation, we find that the injuries are distributed as 
follows: 
(a) The antennae of the first order show the same num- 
ber of injuries. 
(b) The antennae of the second order show the right 
and left to have injuries in the proportion of 14 to 11. 
(c) There were 25 per cent more injuries to the right 
chelipeds than to the left. 
(d) The walking legs of the right side had 26.7 per 
cent more injuries than the left. 
7. Only antennae of the second order and the chelipeds 
showed regeneration. Forty per cent of the antennae of 
the males as compared with 10 per cent of the females, 
showed regeneration, or 28 per cent for both; while 48 per 
cent of the chelipeds of the males and 20 per cent of the 
females or 40 per cent of both revealed a similar condition. 
Conclusions . — The results as summarized above seem to 
indicate that the right appendages are more susceptible to 
