20 D. BRYCE ON THE MACROTRACHELOUS CALLIDIN^, 



musculosa and a form which I take, but with great doubt, to be 

 the hihamata of Gosse. Each has its own peculiar attitude and 

 movement. 



The other species confine themselves to crawling, mostly after 

 the caterpillar fashion, common to the Philodinadw, yet some 

 with a peculiar modification of it noticed both by Gosse and 

 Milne. It is a peculiar mixture of gliding and creeping, and it 

 has been suggested to me that the usual movement of Adineta 

 is of the same character. The effect is indeed the same, but it 

 is produced by very different means. In Adineta the corona 

 has been modified into a mere furring of a ventrally placed por- 

 tion of the head, and the gliding motion is due to the action of 

 the cilia which form the furring of this prone face. In these 

 CallidincB the corona is completely retracted during the progres- 

 sion, and the motion is due to a number of strong cilia which 

 protrude from the hollow tip of the frontal column when fully 

 extended, as in crawling. Thus, so soon as the toes leave hold 

 of the glass, these cilia, by their action on the opposing sur- 

 face, drive the Rotifer forward until the toes can again fasten 

 themselves. The species in which the cilia of the column are 

 so powerful as to produce this gliding movement, possess therein 

 a method of progression distinct from that of any other Rotifers 

 known, in arising from the action of cilia which have no connec- 

 tion either with the corona or with the buccal orifice. 



Another curious peculiarity of some of these forms is their 

 treatment of the food particles after these have passed beyond 

 the mastax. In constricta and some others the food is then 

 formed into small pellets, suggestive of those seen in Para- 

 mecium^ but probably moulded in an oesophagus ; and the 

 capacious stomach presents a very joeculiar appearance when 

 filled with these pellets. An alternate heaving motion provides 

 the necessary agitation of the food. In other species the 

 alimentary canal can be more readily seen to be a long tube in 

 which the food, not moulded into pellets, is agitated by power- 

 ful cilia. In some cases I have not been able to detect the 

 presence of cilia at all. 



It would be unfitting to attempt here even a brief description 

 of the structure of one of these Callidvicv, but as I should wish 

 these notes to have more than a passing interest, I will very 

 shortly indicate some points to which a student should pay par- 



