THE GEPHYREA OF JAPAN. 19 



Papillen " (Fig. 51). The dark-colored apical parts of these 

 papillae are more or less laterally compressed so as to be flattened. 

 The larger ones measure 0.1-0.2 mm. in basal diameter and 

 0.8-0.15 mm. in height. In the remaining regions of the body 

 proper, except at its very anterior end, the papillœ are in general 

 very much smaller and of a bluntly apexed conical shape. In 

 the middle region, the papillie commonly do not exceed 0.05 mm. 

 in basal diameter and in length. In the posterior end they are 

 somewhat larger, measuring 0.1 mm. in average length, and take 

 the shape of a pear-shaped sac with a pointed apex (Fig. 53, 

 PI. III). In the extreme anterior region, the papillae are of a 

 shape quite different from those of all other regions. Here they 

 are no longer conical, but are represented by finger-like processes 

 of about 0.07 7nm. height and 0.04 mm. thickness (Fig. 54). 

 The chitinous wall of such a papilla is, especially on the apex, 

 thick and of a yellowish brown color. On the introvert-basis, 

 there again appear conical papillae similar to those of the body 

 proper. They gradually decrease in size towards the introvert- 

 tip. Fig. 52 represents some papillai from the middle region of 

 the introvert ; here they are seen as transparent, thin-walled 

 processes, 0.04-0.07 mm. high and conical in shape but with 

 the apex rounded. No hook or spine can be found on the intro- 

 vert. The tentacles are simple and not numerous, probably 10 



in number. 



The longitudinal muscles form a continuous sheet. There 

 are two retractor muscles, one of which is very small and the 

 other (the ventral ?) relatively large. The latter arises with two 

 short roots from near the posterior end of the body [rm and 

 nil, Fig. bo). The intestinal convolution {ic) consists of a few 

 irregular spirals unaccompanied by muscles of any sort. There 



