160 ANNALS OF SCOTTISH NATURAL HISTORY 



on the externo-anterior side (" innen abgewandt ") with 5-6 

 bristles from the middle to the apex, and on the anterior 

 side (" innen ") in the middle third with a considerable 

 number of fine somewhat erect hairs. 



The wings are yellowish, especially near the base ; the 

 squamae are yellowish, and the halteres black. 



SOME SCOTTISH ROTIFERS (BDELLOIDA). 

 By JAMES MURRAY. 



THE majority of the rotifers comprised in the order 

 Bdelloida are moss-dwellers. A few species are parasitic 

 on other animals. None are truly pelagic or are found 

 other than casually in open water, but a few species habitu- 

 ally make short swimming excursions among the weeds. 

 Besides moss, they also shelter among other water plants, 

 such as filamentous algns, Myriophyllum, etc. Mosses, how- 

 ever, afford them by far the commonest shelter in a great 

 variety of situations in the fresh water of streams and the 

 margins of lakes, the stagnant water of peat bogs, and on 

 trees, rocks, walls, and the ground, where the supply of 

 moisture is intermittent. Many species, especially of the 

 genus Rotifer, are to be found among the floccose material 

 at the bottom of ponds. Only a few are marine, and those 

 are usually parasitic. Gosse describes a free-living species 

 of Philodina, P. inicrops, which was found in rock-pools in 

 the Firth of Tay, and I have seen two large species of the 

 same genus among washings of seaweed, but could not 

 identify the species. 



The classification of the Bdelloids presents great difficulty 

 owing to the remarkable uniformity of structure which is 

 found throughout the group. The two families, Adinetadas 

 and Philodinadee, are sufficiently distinguished by the 

 different type of corona, but within the family Philodinadae 

 distinctions of generic value are not easily found. As at 

 present defined, the principal genera are distinguished by the 

 presence or absence of eyes, and by the position of the 

 eyes when present. Rotifer has two eyes, placed within the 



