42 ART. 4. T. IKEDA : 



of small granules hardened more or less by the deposition of some 

 calcareous matter. In the middle region of the body proper, the 

 papillae are nearly flat, measuring 0.15-0.10 mm. in diameter. 

 Over their surface there are aggregated numerous irregularly 

 polygonal chitinous plates of various sizes and of a light brownish 

 yellow or true yellow color. One roundish plate in the center 

 is perforated by the opening of the subdermal gland. The caudal 

 shield is of a conical shape and a deep brown color. Like the 

 anal shield, it is constructed of small calcareous granules, and 

 the margin alone is slightly folded radially. Just behind the 

 tentacular region of the introvert, there follow about 35 complete 

 hook-rows. The hook, 0.032 mm. high and yellowish brown in 

 color, is suj^plied with two sharp teeth (Fig. G9). Behind the 

 hook-rows, there are distributed numerous gently curved spines 

 0.045 mm. in height (Fig. 70). The papilhe on the introvert 

 are represented by a small colorless hyaline tube standing on a 

 tubercle-like base (Fig. 71). 



The longitudinal muscle in young specimens is quite continu- 

 ous, while in the adult it is partially divided into indefinite 

 bundles anastomosing very frequently. There are only two re- 

 tractor muscles, the ventral pair, which arise very close to the 

 caudal shield [vm, Fig. 72). For the greater part of their course, 

 they are fused into one band. The dorsal vessel {dv) is very 

 short (about 2-3 mm. in length) and has no contractile villi. 

 The intestinal convolution {;ic) consists of irregular and loosely 

 twisted spirals indicating no definite number of turns. The 

 spindle muscle is, fixed to the body-wall at botli ends. A small 

 blind sac [rg) is attached to the middle part of the long rectum. 

 Only one slender fixing muscle (/m) is present, attached to the 

 first spiral of the intestinal convolution at one end and at the other 



