30 Arenicolidae 



the funnel is fringed with ciliated vascular processes, the margin of 

 the ventral lip, which is not fringed, is either entire, frilled, or 

 deeply notched in the middle. Dioecious, the reproductive organs 

 are borne on the nephridia only. There is a pair of statocysts in the 

 peristomium (except in A. pusilla). 



POST-LARVAL STAGES. Arenicolidae found either pelagic, or semi- 

 tubicolous, living among algae or in sand. Gills absent, or present 

 on a few segments, but small. Prostomium large, conical and 

 overhanging the mouth ; nuchal groove present. Annulation either 

 absent or as in adult. Capillary chaetae and crotchets present in each 

 chaetiferous segment, a transient crotchet in some of the later formed 

 notopodia. An achaetous "tail" in some species. Hearts and 

 nephridia present, the latter have either larval funnels or simple 

 early phases of the adult funnel. Eeproductive organs absent or 

 minute. A pair of statocysts in the peristomium (except in 

 A. pusilla). 



TYPE SPECIES. A. marina (Linnaeus). 



HISTORICAL ACCOUNT. The first mention of a representative of 

 this genus is found in Belon's De Aquatilibus (1553), in which obser- 

 vations are given on the common lug worm, to which Belon gave the 

 name Lumbricus marinus. L. marinus is not mentioned in the first 

 edition of the Systema Naturae, but Linnaeus recorded and figured 

 it in the account (1747) of his journey through West Gothland, 

 and placed it in the sixth and subsequent editions of his Systema. 

 The descriptions of the lugworm given by Pallas, Fabricius and 

 others before the end of the eighteenth century served to bring into 

 notice differences between this worm and the earthworm, which led 

 Lamarck, in 1801, to place these two worms in separate genera. 1 



1 Gervais (op. cit.) states that Boucher d'Abbeville first indicated, in 1798, 

 that the lugworm should be placed in a genus apart from Lumbricus. The 

 writer has searched carefully for publications by Boucher in the hope of finding 

 his remarks on this point, and is indebted for help to M. Ch. Gravier, who has 

 also spent considerable time in the same quest, among the literature of the 

 period, in the Library of the Museum d'Histoire Naturelle, Paris. Only one 

 paper by Boucher, dealing with Lumbricus marinus, can be found (Soc. 

 d'Emulation d'Abbeville, Cl. Sci. et Arts, Rapp. du Trimestre de Vendemiairej 

 An 7), but this does not contain any indication of a division of the genus 

 Lumbricus. Fortunately, there is not even a suggestion that Boucher put 

 forward a name for the alleged new genus, so that there is no danger of the 

 generic name Arenicola, losing priority and falling, as so many other well-known 

 names have done of late, into the limbo of synonymy. 



