70 ARENICOLA MARINA. 



by the open statocyst with foreign statoliths, the single pair of oesophageal pouches, and 

 the small pair of nephri'dia in the third bristled segment. 



A. marina was first described by Belon (1553), and was referred to in Britain by 

 Carew (1602), and by Willoughby more minutely. Most marine zoologists since that date 

 have alluded to this species, which, however, in the southern European seas has been 

 often confounded with other species as shown in Dr. Ashworth's monograph. 



Pallas (1784) in his 'Marina Varia Nova et Rariora ' considers the position of 

 Arenicola as between the Nereids and Lumbrici. 



Gr. Meissner L (1857) found the otocyst or statocyst in Arenicola. 



The Glymenides sulphurea of Claparede 2 (1863) is, as several authors have shown, 

 apparently the young of Arenicola marina, but his drawings of the bristles and hooks are 

 indefinite. 



In Wiren's ' Anat. and Histology of the Limivorous Annelids' (1887) he gives good 

 sections of Arenicola and Scalibregma. In the latter (Plate III, fig. 3) he does not dis- 

 tinguish between the transverse muscle which passes entirely across and above the lateral 

 ventral projections, and the bands which pass on each side into the lateral swellings. 

 The oblique muscle in A. marina he terms transverse. He shows the blood-channels 

 interdigitating between the folds of the digestive system. He gives interesting figures of 

 the circulation. 



Jaquet 3 (1886) describes at considerable length the circulation in Arenicola piscatorum. 



Wilson 4 (1880) and Child 5 (1900) give the early stages of A. crisfata of N. America 

 up to the trochophore stage. Post-larval stages of A. marma were described byBenham 6 

 (1893) and Kyle 7 (1896). Leschke 8 also found similar stages at Kiel. 



Cosmo vici (1880) gave an account of the general structure of A. marina, describing, 

 amongst other things, what he terms the organ of Bojanus developed on minute blood- 

 vessels in connection with his cul-de-sac — both central and peripheral. One set of these 

 organs of Bojanus he associated with the segmental organs which serve for the evacuation 

 of the sexual products. 



Carus (1885) states that this species is termed " Cassoli " at Genoa; at Naples 

 " Esca di fango colla lana in coppa " (Claparede). 



Dr. Charles Davison 9 (1891), from observations made at Holy Island, has calculated 

 that in an acre of sand about two thousand tons are brought up by the lob-worms and 

 deposited on the surface. The effect, therefore, of the action of these annelids on a beach 

 is geologically important. Similar results are detailed more recently by Dr. Ashworth. 



Ehlers 10 (1892) gave an account of young Arenicolaa, chiefly in the pelagic condition, 



1 ' Vergl. Zeitschr. f. rationale Medicin, Bericht./ p. 633, Note. 



2 ' Beobacht. Anat. Entwickl./ p. 30, Taf. xv ; figs. 24—27. 



3 'Mitt. Zool. St. Neap./ Bd. vi, p. 347, pis. xxi and xxii, figs. 50—64. 



4 Observat.on Early Stages Polychast., 'Zool. Anzeig./ 1880; also in f Jonrn. Morphol./ vol. vi, 1892. 



5 ' Arcliiv f. Entwickelungsmech./ vol. ix, p. 587. 



6 ' Journ. M. B. A/ (2), vol. iii, p. 48. 



7 ' Ann. Nat. Hist./ ser. 6, vol. xviii, p. 298. 



8 'Wissensch. Meeresuntersuch./ Bd. v, p. 125. 



9 ' Geol. Mag./ Decade III, vol. viii, p. 489. 



10 'Nach. Koengl. Gesellsch. Wissensch./ Gottingen, 1892. 



