OCR Text |
Show 1897.] NON-MARINE F A U N A O F SPITSBERGEN. 791 fig. 28), and were always free, never within the cast skin of the mother. MACROBIOTUS TUBERCULATUS, L. Plate. Only two specimens of this form were seen. They agreed very well with the original description (" Beitrage," &c. I. c. p. 536) in most particulars, but they were very small, being only j\u"- ECHINISCUS ARCTOMYS, Ehrbg. Specimens of this pretty little species were seen in several of the collections. It may be interesting to note that Ehrenberg first found this species in moss from Monte Bosa, collected at a height of over 11,000 ft. (Weissthor Pass), where the conditions of existence would be not unlike those prevailing in Spitsbergen. ECHINISCUS SPITSBERGENSIS, n. sp. (Plate XLV.) This new species was only seen in one collection, and unfortunately only empty skins were obtained, so that the following description is somewhat incomplete. The back is covered with a series of nine hardened plates, the arrangement of which is in general the same as in other species of Echiniscus. The details of arrangement can best be seen by reference to tbe accompanying drawing (Pl. X L V . fig. 1). All the plates are strongly tuberculated, the tubercles being largest in the central portions of each plate, but becoming smaller towards the margins. There are four pairs of lateral filaments originating from the posterior angles of bead, first, second, and third body-segments respectively. In addition to these there are two loug filaments springing from the posterior margin of the second body-segment, each of which is situated about halfway between the lateral filament and the mid-dorsal line. The posterior margin of the third body-segment is provided with four broad spines-two large, rather closely approximated to the median line, and two very minute, one just above each lateral filament. The two middle claws of the four on each foot are each provided with a little hook near the base (figs. 2 & 3). as occurs also in E. splnulosus, Doy, and E. granulatus, Doy. Length of specimens seen, nearly -j-oV'. Living animals would undoubtedly be somewhat longer, and would therefore appear more elongated than might be supposed from the drawing. Two further species of Tardigrades were also seen during the early part of the examination of the mosses, but the notes taken were not sufficient for specific determination and the animals were not found a second time. Both were probably species of Macrobiotus. One of them was a form somewhat similar to M. tuberculatus, but each of the little tubercles on the back was furnished with two minute prickles. The length was only T^o". The other was a moderately large form, being iy", and possessed the striking peculiarity of having a pharynx nearly three times as long as broad. The Water-bear found by Dr. Goes in 1862 was considered by him to be most closely allied to Macrobiotus dujardlnl, Doy. |