728 Henry B. Ward, 



then the extent and complexity of the lateral ruffles depend on tue 

 State of contraction. They also depend ou the age of the worm as 

 they are simpler in smaller specimens and more complicated in larger 

 ones if both specimens are equally contracted. The depth of the 

 rüffle is affected similarly by age altho not in such a striking fashion. 

 As will appear later the lateral ruffles are filled by the follicles of 

 the vitellaria and undoubtedly develop in connection with the growth 

 of those glands. I do not doubt that a careful microscopical study 

 of such smal specimens asLönnberg mentions would show that the 

 folds and the vitellaria which they contain were relatively less 

 developed and that a great part if not all of the difterences in the 

 folds as described by various authors may be attributed to the age 

 and stage of contraction of the animals observed. 



A most conspicious structure at the posterior end in both living 

 aud preserved specimens is the terminal rosette. Its appearance and 

 movements during life are described at length by Watson; but some 

 further features have been disclosed by a careful examiuation of my 

 specimens that are important for the understanding of this organ 

 and of the animal itself. 



Viewed from the plane surface the rosette. to employ this most 

 appropriate term suggested by Spencek, appears as a tuft of folds 

 circular in outline, turned a little towards this surface, but directed 

 on the whole posteriad. Its relation is distinctly aualogous to that 

 of the terminal sucker of leeches. The folds of which it is composed 

 are so closely crowded together and so complicated in their con- 

 volutions that one can not distinguish any pattern or arrangement 

 (Fig. 10). As folds they stand in striking contrast with the lateral 

 folds of the main body already described. The rosette folds are thin, 

 delicate, semitransparent, sharp edged, not lobed or incised, and all 

 nearly equal in length so as to give a uniform level to the general 

 surface of the organ they form. The surface margins of the folds 

 weave in and out in a labyrinthine pattern which resembles in 

 striking fashion the rosettes of paper or cloth used for ornamental 

 purposes. It is impossible to distinguish on extern al view any 

 structures within the substance of these folds while their thinness 

 and translucency appear to preclude the presence of much tissue of 

 any sort. A study of sections demonstrates that the circular muscles 

 are less conspiciously developed than in the body generally. The 

 ultimate folds have no flbres or only very few and the subcuticula 

 is clear and often displays a vacuolated character. Possibly this 



