COLLECTED BY THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 215 



The bristles are of the forms characteristic of N. dumerilii. Two or three homo- 

 gompb falcigers, with free appendages, occur on the inferior margin of the notopodial 

 bundle in the more posterior para pods. 



The parapods (figs. 12-13) are of normal form, except that the notopodial cirri are 

 of extraordinary length, and the neuro-setigerous lobe in the round-lobed parapods 

 (5th llth pairs) is more prominent than usual. 



The noto-cirri are longest about the 15th~'JOth pairs, behind which they grow 

 somewhat shorter. The ueuro-cirri are also unusually long, distinctly overpassing the 

 neuro-ligules. 



The tentacular cirri are of great length, the longest reaching approximately to the 

 20th setigerous segment. 



On the head there are peculiar markings (fig. 11): a broad ring of dark brown 

 granular pigment exists on the basal joint of each of the palps, and a band of similar 

 nature on the forehead surrounds the bases of the tentacles. Otherwise the specimens 

 preserved in alcohol have lost their colour. 



The extraordinary elongation of the parapodial and tentacular cirri in these 

 examples seems to justify their being assigned a distinct sub-specific name. So far 

 as I am aware, the only other species of nereid which shows a similar development 

 of cirri is N. mirabilis, a member of quite a different group. 



Judging from the position in mid-Atlantic where these worms were collected, one 

 may suppose they had drifted across from the neighbourhood of the Gulf of Mexico 

 with the south-west wind drift; but whether this variety of N. dumerilii characterised 

 by such peculiarly elongate cirri has been evolved solely under the conditions of the 

 drifting weed of the Sargasso Sea, or whether it is also to be found in the littoral 

 areas of the seas of Central America, is a matter for future investigation. 



EXPLANATION OF PLATE. 



Figs. 1 and '2. Nereis pelarj><-, Lin. Smith Africa. 



Fig. 1. Bead and everted proboscis, dorsal view, x 18. 



,, 2. Proboscis everted, ventral view. x 18. 



Figs. 3 to 10. X. falLlawU'-ii, n. sp. Falkland Islands. 



Fig. 3. Head, from above. x 15. 



4. Maxillary ring of proboscis, dissected from the ventral side. x 15. 



,, 5. liasul ring, dissected from ventral side. x 15. 



6. Jaw dissected out, ventral aspect. x 15. 



,, 7. 10th parapodium. xi'l. 



8. 51st ,, x 21. 



9. 70th x21. 



,, 10. Falcigerous seta, from inferior neuropodial bundle "f loth parapndimn. Zeiss 4 D. 



(ROY. soc. EDIX. TRANS., vm.. L., 47.) 



