NYMPHONIDAE 31 



The auxiliary claws are usually well developed, but may be absent or, as in one case, 

 vestigial. The presence or absence of these claws has been used as the first division in 

 Key II, which is not concerned with possible relationships between the species, because 

 this character is (i) convenient and (2) is, so far as our knowledge goes, constant for 

 each species at all stages from immature to adult, and in both sexes. 



The third leg is 5-7 times as long as the trunk, and either smooth or slightly setose 

 in group I. In group II it is 3-4-5 times as long as the trunk in all forms except A'^. capense 

 and A^. compactiim (6) ; while the legs are usually very setose, the two species just 

 mentioned and A'^. articiilare are again exceptions. 



Synonymy. With regard to synonymy, A^. gmcillimum, Caiman, may prove to be the 

 same as A^. hiemale, Hodgson; A^. charcoti, Bouvier, with A'^. lanare, Hodgson, and 

 A^. biarticulatum, Hodgson, with A'^. brevicaudatum, Miers. 



SYNOPTIC KEY TO THE DETERMINATION OF THE ADULT MALES 

 OF ANTARCTIC AND SUB-ANTARCTIC SPECIES OF NYMPHON^ 



I. Segment 5 of (J oviger long and narrow, straight or distinctly curved, of approximately 

 uniform diameter throughout. 



A. Auxiliary claws absent [tarsus and propodus both elongated, subequal, without spines 

 on ventral margin; second coxa long, segment 5 of (J oviger straight (type I)]. 



1. Less than 20 (10-13) spinules on each finger of chela; 21-24 denticulate spines on 

 oviger; 9-12 low femoral gland-tubercles; first tibia the longest segment; claw 

 three-fifths of propodus N. proceroides, Bouvier 



2. More than 20 (28-42) spinules on each finger of chela; 24-34 denticulate spines 

 on oviger; 6-7 femoral gland-openings, but no raised tubercles; second tibia the 

 longest segment; claw subequal to propodus A^. teniiipcs, Bouvier 



B. Auxiliary claws well developed [second tibia the longest segment]. 

 I. Segment 5 of (^ oviger straight (type I). 



a. Number of denticulate spines less than 50 (30-46). 



i. Two terminal palpal segments together equal to or slightly longer than 

 second segment; tarsus rather shorter than propodus; 12-16 femoral gland- 

 openings — low tubercles occasionally present N. hiemale, Hodgson 



ii. Two terminal palpal segments together rather shorter than second segment; 

 tarsus considerably longer than propodus; 10 low femoral gland tubercles 



N. graciUiimim , Caiman 



b. Number of denticulate spines exceeding 50 [14-22 spinules on each finger of 

 chela; 13-16 small femoral gland-openings] N. gracilipes, Miers 



1 Use in conjunction with Table III, p. 28; the large Roman numerals in the left-hand column of table 

 represent the five primary subdivisions of the key. Slight discrepancies in the numbers of spines on the 

 fingers of the chela or of the oviger may occur, but are not important — e.g. in Table III the number of 

 spines of each finger of the chela of a single specimen of A^. longicoxa is given, while in the key the lowest 

 and the highest number of spines on the movable finger of several adults is given. In Table III the ratios 

 represented by fractions are only approximate ; where decimals are employed a higher degree of accuracy 

 has been aimed at. 



