. The Danish Ingolf-expedition. Marine animals -- Arctic regions; Scientific expeditions; Arctic regions. RHIZOCEPHALA OF THE NORTH ATLANTIC REGION is based on the form and the direction of the testes, the situation and the structure of the colleteric glands (Kittdriisen, glandes colleteriques), and the place of the mesentery. Diagrammatic figures of the genera dealt with in the present paper (with the exception of Lernceodiscus only) are given in fig. i. The two genera of the Peltogastridae found in the North Atlantic are Peltogaster and Traclielosaccus. The mantle opening is situated
. The Danish Ingolf-expedition. Marine animals -- Arctic regions; Scientific expeditions; Arctic regions. RHIZOCEPHALA OF THE NORTH ATLANTIC REGION is based on the form and the direction of the testes, the situation and the structure of the colleteric glands (Kittdriisen, glandes colleteriques), and the place of the mesentery. Diagrammatic figures of the genera dealt with in the present paper (with the exception of Lernceodiscus only) are given in fig. i. The two genera of the Peltogastridae found in the North Atlantic are Peltogaster and Traclielosaccus. The mantle opening is situated in the anterior region, the testes run along the mesentery and open backwards into the mantle cavity. In Peltogaster (including Chlorogaster) the stalk is found at about the centre of the dorsal surface (fig. i a). This also holds true for the greater part of the other genera of Peltogastridae, viz., Septosaccus and Dipterosaccus, whilst in Peltogaster-ella the stalk is situated at the posterior extremity (cf. Kriiger, '14). In Traclielosaccus the stalk is also found at the posterior part of the body, but here it is directed towards the ventral region of the animal. The situation and form of the testes and colleteric glands in this genus is approximately the s same as in Peltogaster, the testes of Traclielosaccus also open back- wards into the mantle cavity; the vasa deferentia, however, are directed towards the ventral sur- face (fig. 1 b). The genus Heterosaccus does not occur in the North At- lantic region, but species of the two other genera of the family Sacculinidae are found in this region. The differences between these two genera are represented Fig. 1. Diagrams illustrating the situation of the inner organs in different Rhizocephala. in figs. I C and d\ in SaCClllitia the a, Peltogaster; b, Traclielosaccus; c, Sacculina; d, Drepanorchis; e, Clistosaccus; I. Svlon. , , . , testes have a more or less straight , mantle cavity; mes., mesentery; , mantle opening; s.,
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Keywords: ., bookcentury1800, bookdecade1890, booksu, booksubjectarcticregions
