133 
Jersey and has been figured, probably from the coast of 
Normandy, by Milne Edwards in the plates of Cuvier’s 
* Regene Animal” (dition de Disciples, Plate VIII., Fig. 
1), where it may be recognised by its characteristic gills. 
From the records of A. marina, made by Scandinavian and 
other naturalists who have examined specimens from 
northern seas, it would appear that the littoral variety is 
the only one with which they are acquainted. 
DISTRIBUTION. 
Arenicola marina has been recorded from both sides 
of the Atlantic, e.g., from the shores of Western Hurope, 
Norway, Spitzbergen, North Siberia, Iceland, Greenland, 
and along the northern coast of America from the Bay of 
Fundy to Long Island.” — Latitude 40° N. marks approxi- 
mately the southern limit of A. marina on the Atlantic 
shores. South of this it is replaced on the American 
coast by «A. cristata, and in the Mediterranean by A. 
claparedii and A. cristata. 
EXTERNAL CHARACTERS. 
The description of the external characters of 
Arenicola will be better understood after a brief reference 
to those of some other Polychet, such as Verezs, in which 
the segmentation is more clearly shown. 
At the anterior end of Verezs is the distinct ‘ head,” 
at the posterior end the “tail,” while the intervening 
portion is sub-divided by a series of shallow grooves into 
a number of segments which are practically identical in 
their external characters except in size. Each segment 
bears laterally a pair of muscular out-growths provided 
with bundles of bristles, or setee, and with certain sensory 
* It is also reputed to occur on the shores of Vancouver Island 
and in Angra Pequena Bay (West Africa). 
