Archey. — Fresh-water Crayfish of :\'ew Zealand. 



301 



a tooth placed anteriorly on the inner edge. In all the crayfish I] have 

 examined I have never seen this tooth as pictured by Dana. There is, 

 however, in some of the specimens a rather sharp turn in the sweep of the 

 edge of the squame, which, if exaggerated, might suggest a spine or tooth. 

 The specimen examined by Dana was obtained from Bay of Islands. 

 I have not seen any crayfish from this locality (the most northern ''forms 

 I have examined are from Manukau Harbour), and therefore cannot sav 

 whether a variety with this character actually exists, or whether the artist 

 has exaggerated the " corner " on the inner edge of the squame. 



X. Length of Carapace in Proportion to 



The measurement was taken from the tip 

 of the posterior edge of the carapace. Th 

 groups with regard to this character is that 

 the Rotoiti and Thames specimens have a 

 somewhat shorter carapace ; but in each 

 locality where male and female specimens 

 were obtained the female has a shorter 

 carapace than the male. 



XI. Chelae ; Propod Length -r- Propod 



Breadth. 



The average proportion for S is 3-36, 

 that for $ is 3-16, indicating that the 

 propod of the female is slightly broader 

 than that of the male. 



XII. Spinulation of the Chelae (fig. 5, 



a and 6). 



There is usually a single spine on the 

 lower surface of the basis, though there 

 may be 2 or 3 in large individuals. In 

 small specimens the upper surface of the 

 ischium is smooth, but in moderate-sized 

 individuals it becomes toothed with from 

 3 to 5 edentations. From its lower surface 

 2 sharp spines project, with from 1 to 6 

 smaller spines or tubercles lying between 

 them. 



On the upper edge of the merus there 

 are 2 rows of irregularly placed spines, the 

 outer row consisting of 2 or 3 small 

 tubercles posteriorly, and 3 or 4 spines 

 anteriorly. The lower surface has 2 rows 

 of either 5, 6, or 7 spines. A sharp spine 

 is present on each side of the anterior end 

 of this joint, and sometimes there is a 

 complete ring of about 7 spines here. This 

 ring is particularly noticeable in Napier, 

 Hawke's Bay, Wanganui, and New Ply- 

 mouth specimens, and in some Ross and 

 Nelson specimens. 



the Length of the Body. 



of the rostrum to the middle 

 e only indication of localitv 



Fig. 5. — Chela of P. planifrons : 

 a, from above ; 6, from below. 



