THE GEPHYREA OF JAPAN. 13 



face of the body there are sparsely distributed papilke. Iii the 

 posterior region of the body proper, these are very large and 

 long, measuring 0.125 iiiiii. in height and 0.054 mm. in thick- 

 ness. Each papilla is covered with a number of small chitinous 

 granules of a reddish brown color ; the apex is bored through 

 by a small pore leading into the subdermal gland (Fig. 39). To- 

 wards the introvert-basis, the papilke become gradually shorter 

 and shorter, until in that region they are very short and assume 

 the shape of a round disc of a yellowish color (Fig. 40). Fine 

 radial striation is found in the central chitinous plate containing 

 the aperture of the subdermal gland. The more anteriorly 

 situated papilke of the introvert are once again more prominent 

 and those close to the hooked region have the form of a moder- 

 ately tall (0.04-0.07 mm.), round-pointed process covered with 

 small chitinous granules of a yellowish color (Fig. 41). The 

 hooks (Fig. 42), without being arranged in ring-rows, are ex- 

 tensively distributed behind the tentacular region of the introvert. 

 They are 0.22-0.13 mm. high, slender and almost straight ; and 

 of a brownish yellow color. 



The longitudinal muscles are quite continuous and the inner 

 surface of the body-wall is shiny like a pearl. The retractor 

 muscles {dm., vm., Fig. 43) are three in number, the right ven- 

 tral retractor being absent. The left ventral retractor {v7n) 

 arises at the beginning of the middle third of the body proper, 

 close to the nerve-cord, while the two dorsal retractors {dm) 

 originate immediately behind the anus {a). The two muscles of 

 the left side are entirely coalesced into one band, and anteriorly 

 are again joined to the dorsal retractor of the right side. In 

 spite of the absence of the right ventral retractor, the sexual 

 organs {sx) are symmetrically developed as two slender transverse 



