Morphometric data were collected for 410 specimens ofpareledone turqueti and P. polymorpha caught around South Georgia. The two species differ in beak morphology and in the male hectocotylus. The species have similar appearances although there is a small but significant difference in the mantle lengthbody mass relationship for females, with P. polymorpha having a relatively longer mantle. There is no significant difference in the arm lengthbody mass relationship between species or sexes (p >

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... 5), except in the case of arm IV of females. There is an interspecific significant difference between sucker number on arms I and I1 of males, arms I-IV of females, and between hood length and mass of the buccal mass ( p c 0.05), with P. turqueti having relatively lower sucker numbers, a longer hood length and greater buccal mass mass. The beak of P. turqueti is similar to that of Eledone spp. but P. polymorpha has a small, fine beak with the rostra1 tip ending in an elongated, sharp point. Differences in beak and buccal mass suggest that these sympatric species occupy distinct trophic niches and that the differing morphology of the male hectocotylus is a factor in reproductive isolation.