. Cephalopoda. Cephalopoda. thus slender, with large, terminal, transverse-rhomboidal to heart-shaped fins, pointed posterior end, rounded, dorsoventrally flattened head, slender arms and strong tentacles. Like all Metateuthoidea, this "Protoegops" was probably a permanent swimmer with a social mode of life. In contrast to the Metateuthoidea myopsida (p. 150), we assume that it inhabited the open sea, far from the coast and bottom and entered deep water (luminous organs). The Oegopsida contain the best swimmers of all Cephalopoda, the species of the genus Stenoteuthis (see below), th
. Cephalopoda. Cephalopoda. thus slender, with large, terminal, transverse-rhomboidal to heart-shaped fins, pointed posterior end, rounded, dorsoventrally flattened head, slender arms and strong tentacles. Like all Metateuthoidea, this "Protoegops" was probably a permanent swimmer with a social mode of life. In contrast to the Metateuthoidea myopsida (p. 150), we assume that it inhabited the open sea, far from the coast and bottom and entered deep water (luminous organs). The Oegopsida contain the best swimmers of all Cephalopoda, the species of the genus Stenoteuthis (see below), the habitus of which closely resembles the ancestral form outlined FIGURE 106. Main types of gladius in the Oegopsida. a) Gonatus fabric ii, young form, 5/4x (cf. Figure 115); b)Abralia veranyi, natural size (after Pfeffer, 1912,Plate 16, Figure 7); c) Teleoteuthis i nt er m edi a, 3/2x (after Pfeffer, 1912, Plate 2, Figure 6); d) Brachioteuthis rii.^ei, natural size (after Pfeffer, 1912, Plate 25, Figure 5); e)Pyroteuthis magaritifera, natural size (after Pfeffer, 1912, Plate 19, Figure 21). Note the variation of the different parts. The cone (8) varies from flat and spoonlike to conical; the rostrum (9) may be absent or strongly reduced, despite the thin sheath of the cone. The cone flag (7) may pass gradually into the flag (lateral plates (4,6)) (c,e). The rhachis (1,2) differs markedly in relative length and width, from sharp to blunt. The flag may be reduced (d). Compare the structure with Figure 62 on p. 146; the position in the body and the topographic relationships with those in Figure 65 on p. 153. The general structure of the gladius is typical for all Metateuthoidea. The gladius (if parts are not reduced) consists of rhachis, lateral plates, cone flag, cone, and a usually indistinct rostrum. 226 The relationships between mantle and shell of Protoegops are assumed to resemble those of the Loliginidae (Figure 66b on p. 157), although the postembryonic growth of t
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Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectcephalopoda
