Arenicola ecaudata 137 



determining with certainty. Prof. Fauvel states that, in the neigh- 

 bourhood of Cherbourg, the period of maturity of A. ecaudata extends 

 through a considerable part of the year, for from the end of March 

 to the beginning of October he has found individuals dilated with 

 reproductive products. 



Nothing is known regarding the form in which the eggs of this 

 species are deposited. The early development is also unknown, the 

 earliest stages observed being post-larval examples, about 4*5 mm. 

 long, with about fifty chaetiferous segments. These are abranchiate 

 and remain in that condition until about sixty fully formed 

 segments are present, then gills begin to appear, generally on the 

 sixteenth to nineteenth segments inclusive, and are subsequently 

 formed on the following segments. 



Post-larval stages range in colour from reddish or pale greenish 

 yellow to dark green ; the first two or three segments and the 

 pygidium are generally darker than the rest of the worm. These 

 stages are found near low-tide mark, among algae, for instance, 

 among the " roots " of Laminaria, or in the crevices of Lithotliamnion. 

 When their gills have become well developed, and for the most 

 part ramified, the worms leave the crevices in and among algae and 

 begin to burrow in sand or gravel. 



Most of the post-larval specimens recorded have been collected 

 in July, August or September, but Prof. Fauvel has found them also 

 in April, and M. Ferronniere in March. Mr. Southern took them in 

 numbers in October, 1910, and obtained a single specimen in 

 March, 1911. For an account of post-larval specimens see p. 80. 



DISTRIBUTION. Arenicola ecaudata has been obtained from several 

 widely separated British localities ; it has been recorded from 

 Shetland, Berwick, Devon and Cornwall, the Isle of Man, Cumbrae, 

 Loch Maddy, and the writer has seen examples * from Loch Sween ; 

 in Ireland the species is known to occur in the north (Antrim), east 

 (Co. Dublin), west (Galway and Mayo 2 ) and south-west (Valencia 

 and Crookhaven 2 ). 



This species has been found in the Channel Islands, and at several 

 stations on the north coast of France, namely, in the neighbourhood 

 of Cherbourg and at Kerity ; on the west coast, it has been recorded 

 from Finistere, the Loire estuary and Arcachon, this last being the 



1 In the collection of Prof. J. Graham Kerr, F.E.S. 



2 The specimens from Blacksod Bay, Mayo, and from Crookhaven were 

 collected by Mr. R. Southern. 



