OF DENISON UNIVERSITY. I3 



A careful study of the adult shows that the shell is covered with 

 hairs. These hairs are very conspicuous in stage A. The shell of the 

 adult is marked with very conspicuous dark bands. 



An effort has been made to discover at what period these bands 

 appear, and to see if they conform to the rules laid down by Professor 

 Eimer. The characteristic bands on the shell may be present in any 

 stage from A to the adult; and when they are present they do not 

 differ essentially from the markings on tiie adult. The chief points of 

 difference being variations in the width of the bands. In all examples 

 of stages C and D examined, these characteristic markings were 

 found; but in stages A and B, they were occasionally absent. An 

 examination of figure 35 will show that some of these bands are longi- 

 tudinal while others are oblique. 



Professor Eimer has attempted to establish the followmg rule for 

 the formation of oblique markmgs on animals.' Oblique markings 

 first appear as longitudinal lines. These lines become resolved into 

 dots, these dots, in turn, rearrange themselves in oblique lines. If 

 these laws were applicable to the markings on Cypris Herricki^ in 

 stages A and B, where we have some specimens with bands and 

 others without them, we ought to find some transition stages — some 

 stages in which the oblique markings were represented either by par- 

 allel lines, or by series of dots. But such is not the case. The shell 

 is either unmarked by bands, or both oblicpie and longitudinal bands 

 are present. 



As stated above, in stage A the appendages have practically 

 assumed their permanent form. The post-abdomen is a notable excep- 

 tion. This appendage is quite rudmientary ; not only has it not yet 

 acquired the typical number of setae, but the longest terminal 

 seta is as long as, or longer than, the remainder of the post-abdomen. 

 This great relative length of the terminal seta is due, not to an over- 

 development of the seta ; but to an under-devolopment of the body of 

 the post-abdomen. That the post-abdomen appears to be the last 

 appendage to development is rendered more striking by the discovery 

 of C. Claus that the post-abdomen appears before the formation of the 

 second pair of legs. In stage B the post-abdomen has developed 

 the permanent number of setae, but the ratio of the length of the 

 terminal seta to the length of the body of the member is much greater 



' G. H. Th. Eimer. Organic Evolution is the Result of the Inheritance 

 of Acquired Characters According to the Laws of Organic Growth. Translated 

 by J. T. Cunningham, 1S90, p. 73. 



