Archet. — Fresh-water Crayfish of New Zealand. 311 



tion (" total length 4- breadth of abdomen : ") for five ovigerous females, six 

 females without eggs, and ten males, all collected around Wellington :■ — 



Males . . . . . . . . . . . . 4-95 



Females without eggs . . . . . . . . 5-03 . 



Ovigerous females . . . . . . . . 4-58 



It can be seen, then, that the females usually have an abdomen no 

 broader than that of the males, but that when they are bearing eggs their 

 abdomen is slightly broader. This is due not to anv actual increase in size 

 of the abdomen, but to its being slightly flattened, the pleura projecting 

 outwards to a slight extent. 



(F.) Relative Abundance of Males and Females. 



The males and females seem to be present in fairly equal numbers. Of 

 those I have examined, fifty-eight are males and forty-three females; but 

 large collections from the different localities will be necessary before any 

 significance can be attached to these numbers. In comparing the relative 

 sizes of the males and females it was noticed that in specimens from the 

 different localities the male was more frequently the larger. It is to be 

 noted, further, that the largest specimens obtained were three males from 

 Dunedin. Further information, however, is required on this point also. 



Diagnoses of the Species of Paranephrops. 

 Genus Paranephrops White. 



Paranephrops White, Gray's Zoolog. Miscell., No. 2. p. 79, 1842. 

 Type : Paranephrops planijrons White. 



Paranephrops planifrons White. 



Paranephrops planijrons White. Gray's Zoolog. Miscell., No. 2, p. 79, 

 1842. P. tenuicornis Dana, Crust., Classif. and Geograp. Distrib., 

 p. 1433, 1853. P. planijrons Filhol, Institut de France, iii, 

 2nd part, No. 1, p. 429, 1885 ; Chilton, Trans. N.Z. Inst., vol. 21, 

 pp. 242-49, pi. x, figs. 1-3, 1889 ; Faxon, Proc. U.S. Nat, Mus.. 

 vol. 20, p. 678, 1898 (with references); Chilton, Trans. N.Z. Inst,, 

 vol. 32, p. 14, 1900. P. setosus Lenz, Zool. Jahrb., vol. 14, 

 p. 441, 1901. 



Carapace nearly cylindrical, of the same width throughout whole length 

 of the branchiostegites, smooth, or with small tubercles or spines on the 

 sides. Rostrum elongate, triangular, somewhat depressed, margins raised 

 and usually with 4 teeth on each side, under-surface keeled and usually 

 with 2 teeth. Basal scale of antenna long and narrow, tapering from 

 posterior third, with further abrupt narrowing near the end, reaching as far 

 as or beyond extremities of rostrum and penduncle of antenna, Median 

 keel on the carapace extending from the cervical groove to the level of the 

 anterior of the post-orbital spines. Chelae long and narrow, propod more 

 than three times as long as broad, whole appendage densely spined, with 

 spines arranged in rows on the propod, inner margin of propod armed with 

 2 rows of spines, hairs few or absent, Pleura of abdominal segments rather 

 pointed at the infero-posterior angle, anterior edge longer and more convex 

 than the posterior, and fringed with setae, posterior edge sinuous and 

 scarcelv curving forward. 



