BHACHIOPOD A—THOMSON. 
29 
1911. Magdlania joubini Eichler, Deutsche Siidpolar-Exped. 1901-1903, 
Bd. XII (ZooL Bd. IV), Heft. IV, pp. 388-390, Taf. XLII, figs. 5a-c, 
6a, b, Taf. XLIII, figs. 17, 18, Taf. XLIV, figs. 23, 24. 
1911. Campages joubini Hedley, Commonwealth of Australia. Fisheries. 
Zool. Res. F.I.S. “ Endeavour,” 1909-1910. Part 1, p. 114. 
Habitat. —Station 2, lat. 66° 56' S., long. 145° 21' E. (off Adelie Land), 288-300 
fathoms, 28th December, 1913. Sea-bottom, ooze ; temperature 1-8° C. 
Station 3, lat. 66° 32' S., long. 141° 39' E. (off Adelie Land), 157 fathoms, 31st 
December, 1913. Sea-bottom, ooze ; temperature 1-62° C. 
Station 8, lat. 66° 8' S., long. 94° 17' E. (Davis Sea), 60 fathoms, 27th January 
1914. Sea-bottom, red algae and small rocks. 
The only adult shell of this species from Station 3 may be described as follows : — 
Shell in shape resembling a lozenge with rounded edges, considerably longer than broad, 
greatest breadth slightly posterior to the middle, rapidly tapering to a narrow, nearly 
straight front, the sides uniting with the front in marked angles. Hinge line rather 
broad and very obtusely angled. Dorsal valves lightly convex, flattened on top, ventral 
valve strongly convex with a broad median fold. Anterior commissure, with a shallow, 
broad ventral sinuation. Beak of moderate length, erect, beak ridges rounded but 
distinct, foramen of moderate size, mesothyrid, attrite; pseudodeltidium rather narrow 
and low, concave. Surface of valves marked with numerous strong growth-lines 
crowded anteriorly, giving rise to a lamellar structure. Shell substance thin, pores 
very large, 96 to 108 to the square mm. 
The loop is relatively as fragile as the shell, and parted entirely from the crura 
in an effort to remove the arms and other soft parts, but it was observed to be of typical 
Magellaniform pattern, with a very slender ribbon. The septum extends barely to 
the middle of the valve. The excavate hinge plates are narrow and steeply inclined, 
and the cardinal process is small. 
The above specimen differs somewhat in outline from the forms of Magdlania 
joubini previously described, but it possesses the chief distinguishing characteristics 
of that species, viz., the thin shell with large pores and the strong concentric “ sulcations.” 
These features thus appear to mark off from other species of Magdlania a series of shells 
exhibiting considerable variety of form, and it seems best to group them together under 
one species. 
The other examples from Stations 2, 3, and 8 are all young or half-grown shells, 
but they are all easily distinguished from the other associated species by the coarse 
punctation of their tests. One of 9 mm. in length from Station 8 has a pore density 
of 124. Some of these specimens enable the younger stages of the loop to be observed, 
