144 Arenicolidae 



Imperial Academy of Sciences, St. Petersburg. They are both 

 undoubted A. branchialis. 



The three specimens recorded by Grube, from Saint-Halo and 

 Roscoff, as A. ecaudata, are preserved in the K. Zoologisch.es 

 Museum, Berlin, and have been shown by the writer to be examples 

 of A. branchialis. 



Ives' definition of the " species " ecaudata with eleven to fifteen 

 pre-branchial segments and the localities cited Europe, Medi- 

 terranean, Black Sea show that A. branchialis was included. 



The Catanian Arenicola described by Grube had thirty-eight 

 segments, the first eleven of which were abranchiate, and it therefore 

 belonged to this species. 



In Delle Chiaje's account of his examples of " A. piscatorum" 

 the chief characters mentioned are that the worms were reddish 

 yellow, and had thirty-one chaetiferous segments, thirteen to twenty 

 of which bore bi- or tri-partite gills. A specimen with thirty-one 

 segments and twenty pairs of gills would have the first pair on the 

 twelfth segment, as in A. branchialis, and no doubt some of the 

 specimens belonged to this species. Those with thirteen pairs of 

 gills may have been examples of A. pusiila. 



The unsatisfactory nature of the information given by Delle 

 Chiaje regarding " Lumbricus marinus " has already been noticed 

 (pp. 120, 121), and the reasons stated for believing that his series 

 of specimens included one or more A. branchialis. 



BIONOMICS. The habits of Arenicola branchialis are similar to 

 those of A. ecaudata (see p. 135), and the two species have been 

 frequently taken together. A. branchialis is usually found in 

 oblique or sinuous cavities 1 in coarse, sandy or gravelly material, 

 among stones about the mid-littoral zone. Like other species, 

 A. branchialis is more plentiful in situations in which organic matter 

 is abundant ; for instance, in the Bay of Naples this species lives by 

 preference near the mouths of drains, where it is very common (Lo 

 Bianco). Prof. Fauvel found A. branchialis, near Cherbourg, in 

 black muddy sand which gave off an offensive odour; the worms 

 were so abundant there that they were collected for use as bait. 2 

 This species is, however, seldom found in such large numbers, or 

 obtained so easily, as to make its collection for bait worth the labour 

 required. 



1 Saint-Joseph (loc. cit.) found a specimen of A. branchialis, at St. Jean de 

 Luz, in the sand, in a U-shaped burrow similar to that of A. marina. 



2 Bull. Soc. Linn. Norrnandie, ser. 5, ii (1899), p. 67. 



