Pallenopsis and Rigona, with description of a new species

Pallenopsis is one of the earliest-known Pycnogonids, yet it also may boast of being well-nigh the most misunderstood. Its name and exhaustive characteristics were published not until 1880 by Wilson, but as early as 1804 Latreille gave an account of an animal by the name of Phoxichilus phalangioïdes, which lately proved to be a true Pallenopsis. For this original description I beg to refer to my newly published article.1) Wilson has given the following diagnosis of his new genus: „Body slender as in Phoxichilidium, segmented. Rostrum cylindrical. Abdomen slender, simple. Antennae with four joints, large and chelate. Palpi rudimentary, composed of a single joint. Accessory leg present in both sexes, ten-jointed. Legs slender, dactylus with auxiliary claws. Two very unequal pairs of large ocelli." He further mentions the peculiar glandular duct near the middle of the fourth joint of the legs in the male which he supposes to be perhaps of generic significance. The number of known species amounts to more than thirty, which I have enumerated in the following table. They have been arranged after the depths they were caught in. Moreover I have given in the list some characteristics of the animals, clearly showing the most important special differences. Depth. Most species belong to the genuine deepsea-forms, however not a few are found in shallow water; of some others, the depth they live in, is unknown. Moreover the same species sometimes was met with both in the abyss and in much smaller depths. In general the probabilities