THE GEPllYREA OF .lAl'AN. 51 



pentagonal and rarely polygonal. A condition similar to the 

 above has also been noticed by Selen k a (28) in C. mollis. The 

 edges of the external facets are not sharp, but bevelled and are 

 pigmented a deep brown in the fresh state. The center of each 

 external facet, Avliich is perfectly flat, is occupied by a small, 

 deep brown, circular pore of the underlying papillary gland. 

 Skin-papillte are scattered over the entire surface of the body 

 proper, and are so large that they may be detected with the 

 naked eye ; they are especially densely aggregated near the base 

 of the shield. Under the microscope each papilla appears as a 

 slightly prominent body of a brown or yellowish brown color. 

 Its peripheral portion is formed of two irregular but concentric 

 rings of small chitinous plates, while the central portion is roofed 

 by a thill chitinous layer which is often incomplete as shown in 

 Fig. 87. The subdermal gland opens at the center of the papillae. 

 The papill« measure, in the middle region of the body proper, 

 about 0.08 }nin. in diameter. They become gradually shorter but 

 stouter towards the posterior end, while on the other hand they 

 become taller and more slender towards the base of the calcareous 

 shield. On tlie introvert-basis, they are remarkably tall, measur- 

 ing 0.10 m)n. in average height ; they appear as cylindrical 

 l)rotuberances of a coarsely granular appearance (Fig. 88). Chitin- 

 ous granules are distributed also over the non-papillated part of 

 the skin. There are present about 20-25 complete ring-rows of 

 hooks. These are 0.10 inni. high and of a brown color, and are 

 provided with two sharp curved teeth (Fig. 89). As was figured by 

 ÖLUITER from G. javaiiicuiii, there are a few small processes situated 

 just below and inside the accessory tooth. At the hook-basis 

 there lie two small transverse Ijars and two rows of warts (see 

 the above figure). In the interspaces between hook-rows there 



