NO. 1772. ANNELIDS OF THE ARENICOLID^—ASHWORTH. 



21 



The distribution of this species presents a remarkable parallel to 

 that of certain Oligochsetes. Beddard'* has pointed out that the 

 characteristic earthworms of New Zealand are Acanthodrilidge, and 

 that the same family is equally characteristic of Patagonia. This 

 close resemblance, in regard to their earthworms, between Patagonia 

 and New Zealand is accentuated by the fact that the only earthworms 

 known from the intervening localities, the Falklands, South Georgia, 

 Marion, and Kerguelen islands, belong to the genus Acanthodrilus. 

 Beddard regards these facts as evidence in favor of a former greater 

 extension northward of the circumpolar antarctic continent, and he 

 is inclined to believe that this region did not include the Cape of Good 

 Hope. The evidence afforded by the distribution of the earthworms 

 points to a more recent communication between Patagonia and New 

 Zealand than between either of these countries and the Cape of Good 

 Hope. 



The occurrence of Arenicola assimilis in the southern extremity of 

 South America, the Falklands, South Georgia, Kerguelen, and the 

 southern portion of New Zealand supports the view that there was 

 formerly a more extensive antarctic continent. It is noteworthy 

 that the only species of 

 Arenicola known from South 

 Africa is A. loveni Kinberg,*^ 

 which is widely different from 

 A. assimilis in almost every 

 character, a fact which sug- 

 gests that the antarctic con- 

 tinent was not continuous 

 with the Cape of Good Hope, 

 to which conclusion, as we 

 have already seen, Beddard 

 was inclined to come from a 

 study of the earthworms. 



ARENICOLA CRISTATA Stimpson. 



Arenicola antillensis Lutken. 



Fig. 9.— a. cristata, anterior end, dorsal aspect, of 

 a specimen from florida. x4. l, lateral lobe of 

 prostomium; L. N, lip of nuchal organ; M, median 



LOBE OF prostomium; iVl, FIRST NOTOPODIUM; PH, 

 PHARYNX. 



Seventeen chsetigerous seg- 

 ments; eleven pairs of gills, 

 the first situated on the sev- 

 enth segment; gills large, pinnate, their axes generally joined basally 

 by a web-like membrane; the median lobe of the prostomium (fig. 9) 



o F. E. Beddard. A Monograph of the Order of Oligochseta. Oxford, 1895, p. 154. 

 See also, by the same author, A Text-book of Zoogeography. Cambridge, 1895, pp. 

 60, 170. 



& This species, the anatomy and characters of which have not been described, is at 

 present under investigation by the writer. 



