Chilton. — On Nc20 Zealand Frcslncater Crayfish. 247 



groups as in P. planifrons : Group A, two, as usual ; B, three 

 or four, irregularly placed ; C, five, but not arranged so regu- 

 larly on the margin of the carapace as in P. planifrons ; D, 

 six, extending right back to the cervical groove, and running 

 anteriorly into C ; E, one, situated on slight prominence ; F, 

 two ; G, four or five, very strong, extending into H ; H, a 

 row of about seven, extending along the under margin of the 

 groove ; J, the whole brauchiostegite covered with well- 

 developed spines, all sharp and distinct except those on the 

 lower portions, which are rubbed by the legs and are rounded 

 at the end — the spines extend much further up than is usual 

 in P. planifrons, reaching almost to the branchio - cardiac 

 grooves ; K, a group of about eight well-marked spines ; L, 

 two or three small spines along the branchio-cardiac groove on 

 each side. The squame of the antenna scarcely reaches beyond 

 the extremity of the rostrum, and has its inner margin more 

 convex than is usually the case in P. planifrons. The anterior 

 portion of the epistoma is quite narrow, and ends anteriorly in 

 a sharp spine. The great claws are much shorter and stouter 

 than in extreme forms of P. planifrons, and have thepropodos 

 and the fingers thickly covered with dense tufts of hairs, 

 chiefly arranged in longitudinal rows. The ischios and meros 

 are somewhat laterally compressed, so that it will be con- 

 venient in describing the spines on them to speak of the upper 

 and under edges and the outer and inner sides ; the carpus 

 and propodos are more or less vertically compressed, so that 

 we can distinguish here the outer and inner edges and the 

 upper and under sides. The spines on the gi-eat claws are 

 then arranged as follows : — 



Ischios — Upper edge, two blunt spines. 

 Under edge, two sharp spines. 



micros — Upper edge, one row dividing into two at the end, 

 where there are also a few spines irregularly 

 placed. 

 Under edge, two diverging rows, containing four to 

 six spines each ; one large spine at distal end 

 between the two rows, and others placed irregu- 

 larly. 

 The outer and inner sides of these joints without 

 spines. 



Carpns — Spined all round, the largest on the outer and 

 inner edges ; on the upper side the central por- 

 tion is flat and free from spines. 



Propodos — Inner edge, a row of four strong spines. 



Outer edge, two rows, containing about twelve 

 spines each, extending right along to the 

 end of the fixed finger. 



