- Polychaeta :(supplementary) : . 5g 
~ -<"'The notopodial chaetae ‘are in better condition than: those of the type 
which I examined, the great majority of the latter being imperfect at their tips. 
Fully formed chaétae from the Canadian specimen are a little more than 3mm. 
long, and well:preserved ones exhibit: along one side of their distal portion for 
-a distance of about one sixth the: ength of the chaetae-a narrow lamina, but 
this does not reach-the tip'of the chaetae and its maximum width is not more 
than 6u. On the ‘margin opposite the lamina; and all round the terminal 
portion of the ‘chaetae, are’ ‘fine spines..closely pressed to the shaft. | Theze 
chaetae.are similar to those of A.-marina, except that the lamina is not so well 
developed “and thé spines are rather more slender than in: most examples of 
A. marina; but:specimens of the latter from different: localities exhibit’ some 
variation in the spines of their chaetae, |. ~ ee ae 
-. The neuropodia are elongate in the posterior segments; owing to a certain 
‘amount of maceration their crotchets have fallen out and are’not available for 
‘examination. ~ ST SS gea in Wy te a at ee 
The -nephridia correspond in number and in position with those of the 
type. The funnel of the first. nephridium lies on the anterior face of. the thitd 
‘septum. The funnels are: not -in good préservation, but they are apparently. 
similar to those of A. marina.:. In Fig. 47 (1912) the funnel of the first nephrid- 
ium should have been shown:directed forwards and-not medially. - © © ~ 
The oesophageal glands—a single pair—are ‘elongate cones about 7mm. 
in length: (ih é Soe HNO tae 
‘' The septal-pouches are about’ 2 mm: long and resemble those of A. marina: 
They are rather wider than those of the type specimen shown in Fig. 47 (1912); 
they give the impression by their wrinkled surface that the wall is somewhat con- 
tracted, whereas those of the type figured appear to have been more fully extended. 
: The three septa which cross the: coelom at the anterior border of the first, 
third and fourth chaetiferous segnients of all species of Arenicola are well devel- 
oped in this specimen’ *-. 7 te ‘ wate ee 
The left antero-dorsal wall of the’ peristomium was excised and cut into 
serial sections for a study of the-statocyst. The lumen of the statocyst is conical 
about 160 x.150:x 90uin its three-greatest diameters, and is continued into-a 
tube which leads to the exterior.’ The lumen of the tube is narrow; in section 
it isan oval-slit whose shorter diameter at one point is reduced to lus. The 
statoliths—about 50 in number—are small sand-grains, the largest 254 in 
diameter. :Most of the grains are naked, but a-dozen have a-distinct:envelope 
of secreted material, a common condition in statocysts of Arenicola in which 
the connection of the tube with the exterior has become obstructed. 
The specimen from Bernard harbour thus conforms fully to the diagnosis 
drawn up from the fragile types, except that the gill-axes are longer than 
those of the type specimens, but this is due in part to post-mortem maceration 
and elongation. The discovery of this example of A. glacialis extends the 
range of the species a thousand miles east of the only previously known locality, 
and suggests the inference that the species occurs along the whole stretch of 
the arctic shore of northwest America. It would be interesting to know how 
much further eastwards A. glacialis extends and whether its distribution over- 
laps that of A. marina. The nearest localities from which the latter species 
has been recorded are to the east—the west coast of Greenland (e.g., Godhavn, 
Umanak, Préven) and Rigolet, Labrador, while to the west the nearest definite 
locality! is Cape Ragosin in the Kara Sea, where a single specimen of A. marina 
was obtained (Wirén, 1883). 
1 Grube (1851) recdrded under the name ‘4. marina’a single specimen collected by Middendorff during 
his journey ‘‘in den aussersten norden und osten Sibiriens,’’ but no definite locality was given. Grube 
stated that this example was:about two inches in length and possessed only eighteen chaetiferous sezments 
and twelve pairs of gills. These numbers are not normal for any species of Arenicola, and the worm may 
have been an example of A. marina or of A. pusilla with one segment less than usual, or of A. glacialis 
with one segment more.than usual. The specimen is not preserved in the Berlin Zoological Museum 
(where much: of :Grube’s material is.to be found) and enquiries for it elsewhere have: been fruitless. so 
that it is impossible to state to which of the three species named this specimen really belongs. . 
