I). BRYCE ON THE ADINETADJ:. 147 



usual methods of collection are not adapted to secure many 

 bottom-feeding forms. It is more likely that its inability to 

 swim handicaps it very seriously in the struggle for existence 

 in pools and ditches, and especially in such as have but a 

 scanty supply of weeds, and that in such places it is actually 

 scarce as a natural consequence. 



This same inability to swim is not, however, a serious matter 

 to a creature whose existence is passed where a plentiful 

 supply of water is only occasionally present, and would be of 

 still less importance where the supply of moisture is commonly 

 limited to a thin film covering the stems, or drops lodging in 

 the axils of the leaves, as is the case with many mosses. 

 Besides, if unable to swim, this Adineta can move along at a 

 rapid rate, half -gliding, half -creeping, the body, as well as the 

 head, being now flattened and appressed to the surface on 

 which it is creeping. This flattening of the head and body 

 enables it to travel and to feed in a thin film of water too 

 shallow to allow the stouter Callidinae to pass, far less to 

 gather food. 



The modified corona is not able to attract remote food 

 particles, but can only gather in such as are actually within 

 touch, and the animal has further acquired a peculiar method 

 of feeding. Attaching itself by its toes, it extends itself to 

 full length, keeping the face applied to the opposing surface, 

 and gathering in all available particles, then, suddenly pulling 

 itself back, it again extends in a new direction, and, in this 

 way, without shifting its base, it gathers the food from a 

 circular area, moving on at intervals to commence a new series 

 of extensions. In this habit, peculiar to the limited family of 

 which it is the most common representative, I seem to trace 

 the result of feeding in a restricted area, where food is scarce 

 and where every particle must be utilized. 



Thus, the characteristic arrangement of the cilia, while 

 probably detrimental to the existence of the species in pools 

 and ditches, is distinctly advantageous to it in certain moss- 

 habitats. 



There are, however, many of the Notommatadas whose cilia 

 are also arranged upon a face more or less prone and flattened, 

 and which commonly feed while crawling about. In these 

 cases the cilia have usually sufficient power both to attract to 



