. The Danish Ingolf-expedition. Marine animals -- Arctic regions; Scientific expeditions; Arctic regions. BRACHIOPODA. Chart 4. Distribution of Terebratulina septentrionalis (Couth.). illv striated by moans of very close lying septa, ami more or loss densely set with small slender asperities only visible to high magnification. The hinge line is almost straight and very broad, and the pedicle foramen is a longitudinal gape in the ventral valve; the cardinal processes are slightly or not at all developed; the number of radiating ribs is only small; they are strongly nodulous. No growth-lines hav
. The Danish Ingolf-expedition. Marine animals -- Arctic regions; Scientific expeditions; Arctic regions. BRACHIOPODA. Chart 4. Distribution of Terebratulina septentrionalis (Couth.). illv striated by moans of very close lying septa, ami more or loss densely set with small slender asperities only visible to high magnification. The hinge line is almost straight and very broad, and the pedicle foramen is a longitudinal gape in the ventral valve; the cardinal processes are slightly or not at all developed; the number of radiating ribs is only small; they are strongly nodulous. No growth-lines have yet developed. Fig. 2 shows one of these juvenile specimens, c. 4 mm long and with 12 radiating ribs. During growth the outline of the shell alters, becoming more bulky and proportionally broader, the number of ribs increasing partly bv bifurcation and partly bv interpolation of shorter ribs, retardation in the growth being indicated bv the appearance of the concentric I - at irregular intervals. Furthermore, changes occur in the shape nl' the binge line which becomes shorter and angular, and in the foramen which becomes more circular in correspondence with the development of the cardinal processes. Finally it maybe mentioned thai when the animal has attained a certain size of about 7—8 mm the long seta' of the mantle brim diminish in number, and in fully grown specimens they seem to disappear altogether. A comparison nl' the two drawings of tig. 1 and tig. 2 illustrates this. As shown on the chart T. reiusa is fairly common on the ridge between Iceland and Scotland, along the coasts of Scotland, ami the west mast of Ireland. It belongs to the epifauna of the shell'in these areas and is only seldom found outside the 000 m line. There seems to be no doubt that it especially inhabits the part of the North Atlantic (between 50° and 65° N. Lat.) influenced by the warm Gulf Stream water, the finds outside this area (Finmarken, Helmcke 1939 a. o.) being quite sporadic. As regar
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Keywords: ., bookcentury1800, bookdecade1890, booksu, booksubjectarcticregions
