264 Soiitlicyn Cross. 



Antarctic, but it undeniably obscures the limits of the genera 

 Harmothoe and Lctfjisca. Ehlers (1897) has also expressed himself 

 in doubt as to the relations of these two genera in Antarctic waters 

 (see below, p. 266). 



1. HAEMOTIIOii SPINOSA. 

 (PL XLL, tig8. 1-4, and PL XLIII., figB. 1-2 aud 4-8.) 



Harmothoe spinosa, Kinberg, J. G. H., 1855. 0/v. Ak. Fork., Stockholm, 

 p. 386. Id., 1857. ' Eugenies Resa,' p. 21, Taf. VI., fig. 31. Ehlers, E., 

 18!:)7, Polychaeten, Ilarnhurfj. Magalhaens. Sammebreise, ix 12. 



This species seems to be the representative, in the Antarctic 

 regions, of the northern species H. imhricata (L.), the principal 

 difference between them, so far as I can ascertain by comparison of 

 specimens, relating to the situs oculorum. In the Antarctic species 

 the four eyes are visible from above, while H. imbricata, as pointed 

 out by Mcintosh,^ show^s only a single pair of eyes in dorsal view, 

 the anterior pair being concealed below tlie frontal cones. Both 

 species present a very great range of variation in the fimbriation 

 and pigmentation of the elytra, which has been alluded to by Ehlers 

 (1897) and Mcintosh (1900). 



The number of segments, including the buccal segment, frequently 

 adds up to thirty-seven, but this number possibly represents a 

 particular condition in which the worms are commonly taken, and 

 may not have the significance of a fixed quantity. In one case 

 twenty normal segments are followed abruptly by twelve to thirteen 

 small regenerated segments ; another specimen of 40 mm. has thirty- 

 eight segments ; in a third specimen of 33 mm. the segments, thirty- 

 four in number, taper to a point behind, but no anal cirri are present.^ 



Judging from the material at my disposal, the variations would 

 seem to culminate in three principal allotypic modifications, of which 

 a brief description follows. One of these modifications is for the 

 present retained as a distinct species (see p. 266). 



1 Mcintosh, W. C, 1000: 'British Annelids,' Eay Soc. Monograph, p. 316. 



^ Ehlers (1897) finds thirty-seven segments with length of body increasing 

 from 12 to 45 mm. In this connection it is interesting to note that the 

 number of segments in Lagisca vesiculosa is given both by Grube (1877) and 

 Ehlers (1897) as forty-two. Grube's specimen was 21 mm. in length ; Ehlers 

 gives no dimensions. The larger ' Challenger ' specimens (named L. antarcticu, 

 Mclnt.), measnring up to 36 mm. in body-length, have no more than thirty-nine 

 segments. The number forty-two may very well be final, in which case it will be 

 interesting to learn how it happens that some individuals have less than the normal 

 number of segments, while others nearly half the size have the full complement. 



