MOLLrsCA OF INDIA. 43 



Genus Sagdinella, Morch = P(f/jmrt, juv. 



As I have pointed out in ' Laud and Freshwater Mollusca of 

 India,' p. 45 (1882), the genus Sagdinella of Morch will not stand ; 

 his S. didrichensii turns out to be an operculated form. There are 

 some twenty specimens in Mr. de lloepstorff's collection, in seven of 

 which I detected the operculum. This is multispiral, of about 

 4 whorls, and very thin ; further examination showed that the shells 

 were young PHpincc, the operculum also corresponded. In some 

 shells of P. 7iicQharica, and in the white variety albina, distinct 

 transverse fine ribbing is seen, and on breaking a mature shell back 

 to the same number of whorls as in so-called SagdineUa a precisely 

 similar form of shell was presented. Moreover, this Piqmm, 

 at the commencement of the fifth whorl, contracts very considerably, 

 and the shell is perforate at this stage. On turning to the original 

 description I see that Professor Miirch described it from a single 

 example, and I can quite understand his being misled by this 

 peculiar young form, so very unlike the typical mature shell of 

 Ptipina. I note that in this white very thin variety every grada- 

 tion can be seen, from shells quite smooth and glassy to others most 

 distinctly ribbed. The drawing of SagdineUa didricJisenii given on 

 pi. ix. figs. 1, 1 a, in ' Land and Freshwater Mollusca of India,' 

 was made from the type specimen sent to me from the Copenhagen 

 Museum. 



EXPLANATION OF PLATE LXIII. 



Fig. 1, 1 a, 1 1). Ali/cesus bu^yi, G.-A., x 4. Andaman. 



2,2 c. rubi/ius, G.-A., x 4. Upper Burmah. 



3, 3 a. doherti/i, Q-.-A., X 7. Upper Burmah. 



4, 4 a. subculmcn, G.-A., X 7. Naga Hills. 



5, 5 a. birugosus, G.-A., X 7. Khasi and Munipur Hills. 



6, ffranum,Gr.-A., X 7. Eastern Naga Hills. 



7,7 a, 7 b. ochraccus, G.-A., x 7. Upper Burmah. 



EXPLANATION OF PLATE LXIV. 



Fig. 1. Diplommatina decorosa, G.-A., x 7. Anghami Naga Hills 



2. ambigua, G.-A., X 7. Munipur Hills. 



3,3 a. garoensis, Q.-A., x7. Garo Hills. 



4. commutafa, G.-A., X 7. Lahupa Naga Hills. 



5. tumida,a.-A., x7. ? Typical. N. Cachar Hills. 



6. elongata, G.-A., x 7. Type. Naga Hills. 



7. tumida,G.-k., x7. Munipur. 



8. S a, 8 b. chennelli, G.-A., x 7. Lhota Naga Hills. 



9. hutlt'H, G.-A., X 7. Munipur Hills. 



