«TUDIES ON THE ECT0PARA81TIC TKEMATODES OF JAPAN. ^3 



glands ; but on comparing it with another series of sections I was 

 able to demonstrate clearly their muscalar nature.'-* 



3. Musculature. 



The musculature of the body of the Trematodes consists, as is 

 well known, typically of four sets of fibres, r/i., the circulai; the 

 diagonal, the longitudinal, and the dorso-ventral. There are, however, 

 some variations in ditferent species and genera ; and I shall proceed 

 to note them in the species studied by me. 



In MicrocoUjle, Axine, Uncliocotijk; OclocotijU; Monocolijle, Calicotijle, 

 and Tristomum I find the musculature of the body to consist of the 

 typical four sets of fibres ; but the difterent sets or layers are developed 

 in different degrees in ditferent species. Thus in Microcotijlc, Axitic, 

 Octocotyle, Diclidophora, Monocotiih; and Calicoi[iU; the circular fibres 

 are very fine and are directly applied to the basement membrane, so 

 that they appear in sagittal sections of the worms as minute dots 

 arrana^ed at reofular short intervals. In cross-sections of the worms 

 they are very difficult to demonstrate. In Trisfouunu, on the contrary, 

 the individual circular fibres are stronger and they are generally at 

 some distance from the basement membrane (PI. XXL fig. 4 ; PI. 

 XXIII, figs. I and 7 ; PL XXI\', fig. 1^), le;i\ ing a layer of mes- 

 enchyma of variable thickness between. In (Jncliocotijle and Hcxacotijlc 

 the circular fibres seem to be entirely wanting. 



In Diclidophora an additional l;i,yer of longitiidin;il fibres comes 

 between the circular and the diagonal fibres (PI. X, fig. 4 & PI. XI, 

 figs. 3 & 5). 'ïhe individual fibres of this layer are separated from 

 one another Ijy an inter\'ening mass of mesenchyma ; they are usually 

 o\al or circular in cross-section and are generally a little finer than 

 thi)se of the inner lonofitudinal laver. This layer has also been 



1). Compare on this question the more exhaustive discussions in Monticelli's paper (Primo 

 coutriljuto etc, p. 202 et infra). 



