SCOTTISH ROTIFERS, COLLECTED BY THE LAKE SURVEY. 191 



species of the central group have more gradually tapering spurs. It is nearest P. 

 laticornis, from which it is distinguished by the much shorter foot, slender spurs, and 

 oviparous reproduction. The marked constriction of the jaws above the middle, and 

 the posterior spine, are shared by no other species. All have a prominence at the back 

 of the ramus, and in some it might be called a tooth or blunt spine, but none have 

 such a prominent spine. This is only exceeded in size, among species known to me, in 

 an undescribed African Callidina. 



Rotifer macrurus, Schrank. Common in the mud of ponds, and especially so m 

 peaty bog pools. 



Proales werneckei, Ehr. Parasite in Vaucheria, on which it forms galls ; roadside 

 ditch, Blantyre Moor, near Glasgow. 



Diglena rosa, Gosse. Ponds, Pomona, Orkney. 



Rattulus ca,rinatus, Ehr. Peaty pools, Blantyre Moor. 



R. bicristatus, Gosse. Pools, Blantyre Moor. 



Elosa worrallii, Lord. Pools, Blantyre Moor. 



Stephanops muticus, Ehr. Pools, Blantyre Moor. 



Diaschiza exigua, Gosse. Pond near Mallaig, Inverness-shire. 



Pterodina mucronata, Gosse. Pond at Nerston, near Glasgow. 



Rotifers found among Moss. 



Moss in any situation is likely to contain abundance of Rotifers. In most situations 

 Bdelloids will predominate, but Sphagnum will harbour many other kinds. As a rule 

 the Bdelloids are indifferent to the situation of the moss, and many kinds are found 

 alike in moss which is always moist [Sphagnum and mosses in streams, etc.), and in 

 that which is only intermittently moist (on the ground, walls, trees, rocks, etc.). 



A few species are exceptions to this rule. Microdina paradoxa, for example, will 

 only be found in fresh or running water. The symbiotic species, supposed to be 

 confined to certain hepatics, are quite common in other situations, as among Sphagnum. 



Callidina microcephala, Murray. Ground moss, Fort- Augustus. 



Philodina brycei (Weber) (8). 



One of the commonest Bdelloids in Scotland is P. brycei, and it is often found in 

 lochs. Tt is subject to a great deal of variation. 



Weber's description of Callidina brycei (8, p. 347) is in the following terms : — " Le 

 corps est robuste, allonge, de coloration grisatre ou brunatre. La peau est rugueuse, 

 sillonnee de forts plis longitudinaux sur les faces dorsale et laterales du corps ; par 

 contre, on compte 8 plis transversaux sur la face ventrale. Le bord anterieur du 

 premier segment troncal et le bord posterieur du troisieme segment troncal sont armes 

 chacun, dorsalement et lateralement, d'une rangee de courtes epines. L'organe rotatoire 

 est moderement large, a sillon intertrochal etroit. La trompe cylindrique est longue. 



