50 ART. 4. 1. TKEDA : 



species mentioned, especially in regard to their external features. 

 As to its internal characters, the present species may be said to 

 be almost identical with C. asj:)ergilh(m and C. javanicum, except 

 in the facts that the longitudinal muscle is not separated into 

 bundles and that the sexual organs are not developed in the same 

 position as in C. javanicum. 



The species has long cylindrical body which may reach about 

 7 cm. in length and 7 mm. in width. The posterior end of the 

 body is rounded in the fresh state. As was noticed by Shipley 

 (31) in G. javanicum, the external appearance of the s})eeies is 

 subject to considerable individual variation, but as a. general rule 

 two types of characters are distinguishable. In the one the skin 

 is thick and of a deep brown and the calcareous shield, composed 

 of calcareous papilloe, is as wide as the body proper ; while in 

 the other the skin is thin, nearly transparent and of a reddish 

 brown and the shield, consisting of very small papillœ, is narrower 

 than the body proper. According to my own observations, how- 

 ever, these differences are in a great measure those of the 

 sex. The first type referred to being seen mostly in the male 

 and the second in the female. Fig. 18 is taken from a large 

 male in the living state. 



The anal shield, which shows a structure peculiar to the 

 genus, presents varying shapes according to the state of contrac- 

 tion, a fact previously noted by Sluitek (35) in G. javaniciim ; 

 it assumes all sorts of forms varying from that of a depressed 

 disc to that of a cone. The shield is made up of numerous milky- 

 white calcareous papilLie which are spirally arranged and become 

 gradually smaller towards the posterior border (Fig. 86). The 

 papillœ are mostly of a hexahedric form, but their external facets 

 present rather irregular shapes, being quadrate, rhomboidal, 



