622 



PROCEEDINGS OF THE ACADEMY OF 



[Dec, 



ADDITIONS TO THE JAPANESE LAND SNAIL FAUNA.-V. 

 BY HENRY A. PILSBRY. 



The descriptioa of Japanese ClausiliidoB is resumed in the preseut 

 paper. Enough material is dow at hand to permit some work 

 looking beyond merely descriptive treatment, while every sending 

 from Mr. Hirase adds to the data on one or another of the prob- 

 lems presented by these intricately constructed creatui-es. I have 

 below considered the evolution of the " lunella," as shown in some 

 newly discovered species of Stereophcedusa, in which young shells 

 show a series of distinct palatal folds, like the European tertiary 

 Clausiliidoi and the more primitive forms of Eastern Asia, while 

 old shells have a true lunella. A similar transformation has like- 

 wise been observed in a Mcgaloph(edusa just received. The evi- 

 dence indicates that the lunella has been independently acquired, 

 in different phyla, by a process of parallel evolution. 



Diagrams showing chief modifications of the palatal armature in Eemi- 

 phiBdusa : Fig. 1, C. aulacophord ; fig. 2, C. crenilabmm ; fig. 3, G. attrita ; 

 fig. 4, C. hakonensis ; fig. 5, C. hyperolia ; fig. 6, C. shikokuensis ; fig. 

 7, G. perifjnobilis ; fig. 8, G. munus : fig. 9, G. micropeas ; fig. 11, G. 

 firaeilispira. 



