PART III. of the account of the animals obtained during the above expedition is by the well-known naturalists, D. C. Danielssen and J. Koren, and treats of the group of the Gephyrea. It is illustrated by six plates and one map. Of the ten genera and the sixteen species collected during the expedition four of the genera and seven of the species prove to have been undescribed, and a new family is formed for the remarkable new genus Epithetosoma. This genus differs in many respects from any known genus of the Gephyrea; most notably so by reason of the fissured opening through which the sea water gains access to the perivisceral cavity. The analogue of this respiratory fissure is probably not to be found in the class, but the general organisation of this new form is still truly Gephyrean. Unfortunately but two examples of this interesting form were dredged up, and even these were not well preserved. They were found in sandy clay at a depth of 870 fathoms, in the cold area. In concluding the memoir the authors remark that the two groups into which the class Gephyrea is subdivided, viz. G. inermia and G. armata, can bardly be regarded as satisfactory. Of several new forms which they describe, and which by reason of their anatomical structure they refer to the second subdivision, none are furnished with the armature on which that subdivision is based. Had therefore the systematic classification been rigorously applied, these would have been referred to the first subdivision, one with which they have but little in common, compared to the striking resemblance they bear to those forms comprised in the other. A list of all the species met with and their principal synonyms are appended.
The Norwegian North Atlantic Expedition, 1876–1878.
III. Zoology. (Christiania, 1881.)