410 PROCEEDINGS OF THE ACADEMY OF [July, 



the central group, and Oshima in the northeastern group. There 

 can be no doubt that when other islands are explored many more 

 species will be brought to light, and our zoogeographic knowledge 

 correspondingly expanded. 



The known species fall into five subgenera or sections: Stereo- 

 phcedusa, Luchuphcedusa, Hemiphcedusa, Tyrannophcedusa (?) and 

 Zaptyx. Of these, the section Luchuphcedusa, comprising about 

 half the species now known, has been found nowhere but on these 

 islands. Zaptyx extends into the southernmost provinces of 

 Kiusiu, in the neighborhood of Kagoshima Bay; and probably 

 borne by the " Kuro Shi wo " has reached Hachijo, an islet a 

 hundred miles off Izu province; but a Loo Chooan origin of the 

 group seems probable. Stereophcedusa and Hemiphcedusa range 

 further, being common throughout Japan, and the latter group is 

 widespread on che Chinese mainland ; but the species of the Loo 

 Choo Islands belong to a special group of Hemiphcedusa which has 

 not been found elsewhere. The single species referred doubtfully 

 to Tyrannophcedusa has no close relatives, but seems nearer t 

 Japanese than to any Chinese species known to me. The sections 

 JEuphcedusa and Megalophcedusa, so characteristic of Japan, are 

 wanting in the Loo Choos, so far as present information goes; and 

 Reinia has not been found. So much for the distribution of the 

 groups. Descending to species, we find not one common to the Loo 

 Choo Islands and any other land. 



The general affinities of the Clausilia fauna, we may conclude, 

 are closest with Japan, though the endemic element is so strong 

 that no relationship at all intimate can be claimed. No character- 

 istic Formosan forms of Clausilia have been found in the Loo 

 Choo group. 



Section STEREOPH^EDUSA Bttg. 



Clausilia valida Pfr. 



Originally described from the " Liew Kiew " Islands, this 

 species is known from Okinawa Island only. It has been collected 

 there by the Japanese collectors sent by Dr. Adolph Fritze in 

 1891, by Mr. Frederick Stearns about the same time, and has also 

 been taken by Mr. Hirase's collector. The typical form is uniform 

 brownish yellow. 



