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Transactions. 



was made, and certain proportions calculated for each specimen ; and, in 

 addition, the details of the spinulation or of the shape of different parts were 

 recorded. From the tables thus compiled could be obtained more definite 

 evidence of the existence of different local varieties than by mere obser- 

 vation. 



In arranging the spines on the carapace into groups I have followed 

 the system given by Dr. Chilton (1889, p. 243), and the " group letters " 

 used here refer to the same sets of spines as they do in Dr. Chilton's paper. 

 I have added group K, consisting of 3 or 4 small spines situated above 

 the branchio-cardiac groove, and group L, found only in P. setosus and 

 P. zealandicus, placed on the posterior portion of the gastric area, level with 

 group B. 



A. General Description of Paranephrops planifrons. (See Plate IV, 

 fig. 1. and text fig. 1 ; also measurements, Table 1, p. 313.) 



I. Carapace, Length -r Breadth (column 2). 



There is a slight indication here that the crayfish grow a little stouter, 

 comparatively, as they increase in size ; but the difference is very much 



Pic 1. — P. planifrons White. .Specimen from Ross, Westland. 



less than in P. setosus. There are no local variations with regard to this 

 proportion. 



II. Bulging of the Sides of the Cacapace. 



The sides of the carapace are, in moderate-sized individuals, practically 

 straight, or, at most, with only a slight bulge ; in the larger specimens, 

 however, from Wanganui, New Plymouth, and Napier, there is a distinctly 

 oval carapace, further emphasizing the fact that the animals grow com- 

 paratively stouter as they increase in length. 



