The Rediscovery of Arenicola glacialis Murdoch, with 
Observations on its Characters and on its Status 
By J. H. Asuwortu, D.&c., F.R.S. 
Professor of Zoology, University of Edinburgh 
In the Report of the Canadian Arctic Expedition, 1913-18, Dr. Ralph V. 
Chamberlin recorded (Vol. IX, Part B, pp. 20B-218, 1920) a single specimen 
of Arenicola marina which was taken from the stomach of a sculpin (Cottus sp.)+ 
caught in about two fathoms of water, Station 49h, in Bernard harbour, North- 
west Territories, on 17th June, 1916. 
The only other specimens of the genus Arenicola recorded from the arctic 
shores of northwest America are the examples of A. glacialis Murdoch, obtained 
by the International Polar Expedition to Point Barrow, Alaska, and preserved 
in the collection of the Smithsonian Institution. 
The list of synonyms given under Arenicola marina by Dr. Chamberlin 
includes A. glacialis, an indication that he had overlooked the accounts (Ash- 
worth, 1910, 1912) in which the latter species was held to be distinct. There 
was the possibility that the specimen recorded from Bernard harbour might 
prove to belong to the species glacialis, and in any case a specimen of Arenicola 
from the area in question was of considerable interest from the point of view of 
distribution. I asked Dr. Chamberlin to allow me to examine it, and I have 
to thank him for so freely placing it at my disposal. 
Examination showed that the specimen differs from A. marina and agrees 
with A. glacialis, and this example becomes of some importance, as it provides 
the second record only of the species. 
The orginal specimens of A. glactalis consisted of five picked up on the 
beach (12th Sept., 1882) at Cape Smyth, Alaska, after a fresh westerly gale, and 
two mutilated ones taken from the gullet of an eider duck which had been 
diving on one of the sandy patches in about three fathoms. Murdoch’s descrip- 
tion (1885, 1885a) of the specimens, and his diagnosis of the new species which 
he founded to receive them, gave little information, except that the worms 
were closely allied to A. marina and that they had only eleven branchiferous 
segments (there are thirteen in A. marina). He also remarked on the nature 
of the gill—each being formed of “‘a cluster of about fifteen simple cirri’’—but 
he gave no figures and no account of the internal organs. This insufficient 
description left the status of A. glacialis in doubt; some authors not being 
satisfied with the characters as given regarded A. glacialis as a synonym of. 
A. marina, and others placed glactalis under A. cristata, which also has eleven 
branchiferous segments. 
I had the privilege of examining the type specimens from which I drew up 
an account (1910) of the principal characters—external and internal—which 
indicated that A. glacialis is a valid species, and in this and in a subsequent 
publication (1912) figures of the distinctive features and an adequate diagnosis 
were for the first time provided. 
The characters of the species were stated (1912) as follows:— 
“Caudate Arenicola with seventeen chaetiferous segments; eleven 
pairs of small gills, the first situated on the seventh segment; the gill-axes 
are very short and bear at their distal ends few branches, each of which 
is either simple or divides dichotomously once or twice, the finger- or 
thumb-shaped gill-filaments forming clusters at the end of each axis; the 
1 Now determined to be Myozocephalus scorpioides Fabr. (F. Johansen, Part A, Vol. VI of this series, 
now in preparation. ) 
83042—13 
