ON THE ANATOMY OF HISTRIOBDELLA HOMARI. 309 



anterior feet, while the other set run forward and are inserted 

 ventrally into the anterior part of the jaw mechanism. In 

 the posterior region each baud splits likewise, the ventral 

 sending fibres to the foot of the same side, other fibres cross- 

 ing to be inserted in the small appendage of the posterior 

 limb. The dorsal send part of their fibres into the leg ou the 

 same side, while the internal ones cross over to be inserted in 

 the leg of the opposite side, these fibres thus forming a cross 

 dorsal to the anal part of the gut. The dorsal longitudinal 

 bands give off a few fibres to the two segments of the caudal 

 region, which run towards the median line and are inserted 

 into the cuticle. It is due to the action of these fibres that 

 the contraction of the caudal segment is brought about. 



As already mentioned, the ventral bands split in the head 

 region into two sets of fibres. One of these runs forward to 

 > be inserted in the anterior part of the jaw apparatus, while 

 the other supplies the extensor and flexor surfaces of the 

 anterior feet. The manner of insertion of these last is some- 

 what peculiar. The fibres of the external side of the longi- 

 tudinal band are not inserted immediately into that side of 

 the foot nearest them, but run to the anterior surface of the 

 organ, while those of the inner side of the band cross these 

 to run to the posterior surface. In addition to these there 

 are also other fibres, derived from the bands of the opposite 

 side of the body, that also run to the anterior face of the foot. 

 These fibres form a cross ventral to the anterior end of the 

 stomach. Besides these there are some strands that run 

 from the same side of the foot directly towards the median 

 line, and appear to be inserted into the anterior end of the 

 jaws. All these are inserted into the distal joint of the foot. 

 The course of these different fibres can be readily understood 

 on reference to text-figs. 1 and 2. 



B. Special Muscles of the Generative Segment. 



In the anterior and posterior part of the generative segment, 

 in the intersegmental region, a few transverse fibres are 

 present, running beneath tlie epidermis. 



