246 Proceedings of Indiana Academy of Science 
The largest number of broods with ten to twelve in a brood occurs 
early in the season during the last of June to the middle of August 
(Figure 2), but in the latter part of the season the largest number 
of broods with five to ten in them are found. (Figure 4.) 
Let me suggest that probably the high point of (Figure 2), which 
represents all those females producing from ten to fifteen in a brood, 
represents those individuals breeding which were themselves produced 
the year before. As the season progresses the highest point is changed 
and the number of individuals producing five to ten reaches the largest 
number. There is a smaller number in a brood because younger animals 
are breeding and evidently they themselves were produced early that 
same season. Summing up then we might say that 
1. In the early part of the season there are larger broods, produced 
as a rule, than during the latter part of the season, therefore 
(a) Individuals reproducing in the first part of the season were 
themselves produced during the previous season and are older than, 
(b) Individuals reproducing toward the last of the season which 
were themselves produced early that same season. 
(c) Figure 3 shows the transition stage as occurring during the 
middle of August. That is, the largest number of broods produced 
with ten to fifteen in a brood is being reduced both in number and its 
relative position to the number of broods of five to ten in a brood. 
After the females produce from ten to fifteen young in a brood 
the females seem to gradually die off. (Figure 5.) There could be very 
few reasons for this. 
(a) The females might become barren after reaching a certain 
age but this is unusual in crustacea and I myself never found it to be 
true in the hundreds of individuals examined. 
(b) Died when a certain age was reached, which is not true as 
there would be a sudden drop some place in Figure 5 but it is a gradual 
drop. 
(c) The animals might meet with accidents such as being seized 
and eaten by other animals. This seems to me is the true explanation 
so that an animal increases in age it has fewer companions its own size 
and age. Thus an individual seldom, if ever, reaches a size, which in 
reality represents its age, to produce a brood above the thirty mark. 
ADDITIONAL OBSERVATIONS. 
Holmes (’03) in his discussion of sex recognition among amphipods 
states that the instinct of the males for carrying the females is very 
strong, and that they cling to them by the first gnathopods even when 
injured. His point is that the lack of resistance on the part of the 
female when carried by the male, determines whether she shall be car- 
ried by him or not, and not merely her sex. In corroboration of this 
view I saw a male tugging away at a male who in turn was carrying 
a female. He pulled and tugged while the two ventral amphipods re- 
mained comparatively quiet. If the male carrying the female had not 
been carrying her, he would not have permitted the other male to carry 
him, but he clung to his mate in spite of his unusual position. 
I had the good fortune to observe the process of copulation several 
times which was in detail as follows: 
