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521 
and thickness of the flagellum of the first antenna, the length 
and thickening of the joints of the fifth peraeopod, and in the 
length of the third uropods. The special characters of these 
appendages appear to be attained only in adult specimens and 
possibly they are more marked in the males than in the females. 
In Niphargus chilkensis the parts that are similarly subject 
to special development seem to be the peduncle of the first an- 
tenna, the propod and dactyl of the second gnathopod, and the 
fifth perseopod. 
REFERENCES 
1. Chevreux, E. Biospeologica— Amphipodes. Arch. Zool. Exp. et Gen. 
42 (1909) 27-42, pis. 1, 2. 
2. Chilton, C. Some New Zealand Amphipoda belonging to the genus 
Phreatogammarus. Journ. Zool. Research 3 (1918) 81-86, with text 
figures. 
3. Sayce, 0. A. Niphargus pulchellus, a new Victorian blind amphipod. 
Proc. Roy. Soc. Victoria 12 (1900) 152-159, pi. 15. 
4. Stebbing, T. R. R. Amphipoda, 1 Gammaridea, Das Tierreich, Liefer- 
ung 21 (1906). 
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