ON THE LIFE HISTORY OP UGIMYA. 



25 



of the branches of the vessels. 



Muscular system ( PL IF, fig. 14, 15 ). — The inside of the walls 

 of the body is provided with three sets of muscular bundles — longi- 

 tudinal, transverse and oblique. The longitudinal bundles {fiij. lé a, 

 ßg. 15 a) are two in number and run, one on each side of, and in close 

 proximity to, the ventral median line, thus leaving only a long narrow 

 space between them. They are constricted ti-ansversely at regular 

 intervals, i.e., at the junction of successive segments beginning with 

 the 5th and ending with the last. The longitudinal bundles thus 

 divide the body into two unequal longitudinal parts, a narrow ventral 

 portion and a much larger dorsal portion. The narrow ventral portion 

 is occupied with series of oblique bundles (fig. 14 h, fig. 15 h ), which 

 will be spoken of later. The larger dorsal portion is provided with 

 three superposed layers of muscular bundles. The most external of 

 them are the transverse bundles (fig. 15 c ). Generally there are two 

 pairs to a segment, each bundle starting ventrally from the longi- 

 tudinal bundles and ending close to the dorsal median line. Internal 

 to the transverse bundles is a set of oblique bundles (fig. 14 d, fig. 

 15 d). These arise symmetrically on each side of the dorsal median 

 line, in close proximity to it, from the junction of the segments, and 

 are directed backward and ventralward. They appear to be attached 

 at the joints of the longitudinal bundles three segments behind the one 

 from whicli it takes its origin, but in reality pass under the longi- 

 tudinal muscles and dividing into several branches (fig. 14 h, fig. 15 h) 

 run toward the ventral median line where the bundles of two sides 

 interlock with their extremeties. The most internal set of muscular 

 bundles (fig. 14 e, fig. 15 e) is likewise oblique, arising from exactly 

 the same spot as the last, but taking their course forward and ventral- 

 ward. The two sets of the oblique bundles together with the trans- 

 verse will be seen to present an appearance something like a network. 



