312 CRESSWELL SHEARER. 



In Stratiodrilus their presence has been observed by 

 Hasvvell (13), who states: "Throughout the body slender 

 oblique bundles occur at fairly regular intervals, running 

 from the cuticle of the lateral surface to that of the ventral 

 near the nerve-cord" (p. 306). Here, however, they would 

 seem to be much less developed. I think there is no doubt 

 that they correspond to the oblique muscles of Polygordius. 

 It is interesting to note that the nephridial canals, as in 

 Polygordius, are always within the limits of the lateral 

 cavities formed by them. Another point of similarity consists 

 in the manner of their insertion into the dorsal body-wall. 

 They spread out in a fan-like manner, as Hempelmann (15) 

 has shown takes place in Polygordius (see his text-fig. 14). 

 This same arrangement of the fibres, it will be seen, is found in 

 Histriobdella (fig. 41). The anterior and posterior feet, in 

 addition to the fibres they receive from the longitudinal 

 bands, also possess a special musculature of their own. In 

 the anterior foot this consists of a series of parallel fibres that 

 run from its base to the distal, flat, saucer-like pad of the 

 foot. The foot itself is composed of two parts, a distal 

 retractile portion and a larger non-retractile, cone-shaped 

 basal portion. Some of the fibres are applied closely to the 

 cuticle of the outer part of the basal portion, Avhile those of the 

 bauds, as ah-eady mentioned, are inserted into the retractile 

 distal portion. They surround and run into the basal gland 

 of: the foot. There is a collection of granular mucus cells at 

 the base of the foot, abutting internally on the jaw muscula- 

 ture. They stain deeply with carmine, each cell having a 

 darkly granular periphery, with a clear centre hollowed out 

 in a small cavity. The gland gives off a number of straight 

 tubes, that open on the pad surface of the foot. They run up 

 amongst the muscle-fibres, and can be readily distinguished 

 from these by the manner in which they take the stain. The 

 gland pours out on the surface of the pad some sticky secre- 

 tion, by means of which the animal is enabled to obtain a firm 

 hold. In the case of the posterior limbs a similar, but larger, 

 gland is present. It extends from the wall of the gut out of 



