772 J. H. ASinVORTH. 



the same localily as tlif post-laivtil stages described on pp. 764 



768. Tliere can be no donbt that tlie latter are stages in 



development of I lie former. Judging from Elders' record 

 (1897, p. 104) of the capture near Uschuaia of a gill-less 

 specimen 6"5 mm. long with nineteen cha;tigerous segments, it 

 seems probable that the variety occurs at this place along 

 with typical specimens of the species. 



A^n. Distribution of Arenicola assimilis. 



Elilers (1901, p. 178) records the occurrence of A. 

 assimilis in collections from the Straits of Magellan (Punta 

 Arenas and Susanna Cove), the Beagle Channel (Uschuaia 

 and Lapataia Nueva), South Georgia, Chile (Schmarda), 

 Kerguelen (Grube), and California. 



Schmarda's (18G1, pp. 51, 52) A. piscatorum from Chile 

 and Grube's (1878, pp. 511, 551) A. piscatorum, Cuv., var., 

 from Kerguelen, are both included by Ehlers under the 

 species A. assimilis. Although Schmarda gives a brief 

 description of some points in the anatomy of his specimens 

 he unfortunately does not mention any characters which 

 enable their identity to be definitely settled. With respect 

 to Grube's specimen from Kerguelen the only information 

 given is that most of the branchiferous segments are divided 

 into only four aunuli, and owing to this feature Grube dis- 

 tinguished his specimens as a variety of A. piscatorum. 

 There is no evidence to show that any of these specimens 

 belong to the sj)ecies A. assimilis. 



Ehlers (1897, p. 104) states that in the Gottingen collec- 

 tion there is a species of Arenicola^ from California in 

 which there are twelve pairs of gills which agree in position 

 with those of A. assimilis, and these specimens are dis- 



' 1 lliaiik rrol'cssor Elilers I'ur bciuiiiig to inc by letter the tiuther inroniia- 

 tiou that ihis is a duplicate fiuni i'lufebbor Agussiz's collection, wliicli was 

 sent to Gottingen to be worked over. The rest of the specimens were 

 returned to rrolessor Agassiz, and arc doubtless those referred to on the next 

 page. 



