46 ART. 4. 1. IKEDA : 



animal (Fig. 11) is small, measuring 15 mm. in length of the 

 body proj^er. The introvert is nearly as long as the body proper, 

 but only half as thick. The skin is ver}^ thin, smooth, partly 

 transparent and of a light reddish brown except at the anterior 

 end of the body proper, where it is a deeper brown and of a 

 rough granular appearance. The anal shield may be said to 

 consist of an obliquely conical main part and of a short, cylindrical, 

 basal part. The former has the surface marked with distinct 

 radial grooves. The basal part also shows grooves which alternate 

 in position with those in the conical part (see Fig. 11). The 

 entire shield is formed of small, densely aggregated chitinous 

 jDlates. The caudal shield is in the shape of two cones juxta- 

 posed at base ; it is radially grooved, the grooves on the two 

 cones alternating (see the above figure). The greater part of the 

 body proper shows no papillary structure ; only by using a high 

 power of the microscope can the numberless small openings of the 

 subdermal glands be discovered. Just in front of the caudal 

 shield there are seen some slightly prominent papillary bodies 

 measuring 0.06-0.10 mm. in diameter. They are formed of small 

 polygonal chitinous plates of a light yellowish brown color (Fig. 

 78). Tlie plates are somewhat smaller in the central part of the 

 papilla than in the periphery ; the most centrally situated plate 

 bears the poi-e of the subdermal gland. Around the base of the 

 anal shield, the papilhe are larger (commonly 0.10 mm. in dia- 

 meter) and of a deeper brown than in the posterior region. Vei-y 

 numerous hook-rows are present on the introvert sui-face. The 

 hooks (Fig. 79), 0.02 7nm. high on an average, have a blujitly 

 pointed apex; they are of a light yellow color. Between these hook- 

 rows there are distributed small tubular papillae. No spines can 

 be detected behind the hook-j'ows. 



