144 



TAC.E SKOGSHRRO 



Fi?. XXIII. Diagram to show the results of my measiircmrnls of the leiiRths of the shells of -a number of specimens 



of Kriihe sp. from Villerranche-s-mer. The abscissa represents the lengths of the shells expressed in divisions of a 

 mierometer (64 divisions = 1 mm.); all the measurements are rounded off to thi; nearest half division. The ordinate 



represents tlie number of the speiimens measured. 



The relation between the different succeeding stages, i. e. the g r o w t h - f a c t o r s, 

 is as follows: 



45.1 : 36,12 = 1,248 

 36,12: 28,8 = 1,254 

 28,8 : 23,23 ^ 1.24 

 23,23: 19,2 = 1,21 



19.2 : 15,5 = 1,24. 



Hon- do these exam- How do the examples given by me above stand in relation to Brooks's law, if the 



pies stand in relation j^^^^j. jg ^.^^^j^ as formulated bv G. H, FowLER, 1909, p. 224? 



Cypridina (DoloriaJ pectinata: The agreement between the lengths as calculated theo- 

 ^xanipesjn^^ainn, ^^^^^^-^^^^^^^^^^^^^^^^11^^^^^^ j^ Striking. The males increase, however, comparatively less 



