152 Records of the Indian Musevm. [Vol. XIV, 



L. acuminata^ appear to bear the same relationship to one another as do 

 L. peregra and L. ovata, but in this species the differences are not cor- 

 related with life in still or running water. I have recently examined 



6 



C 



4 



Fig. 5. — Shells of Limnaea illustrating the evolution of deep-water forms. 



a. Type-specimen of L. bowelli from Tibet. 



b. Living form (phase C of L. shanensis) from the Inle Lake. 



c. Fossil form (phase D of the same species) from the bottom of the Inle Lake. 



d. L. auricularin. Form from small streams on the Pamirs. 



e. L. auricularia var. andersoni from the GuK of Bothnia. 

 /. L. Joreli from the depths of the Lake of Geneva. 



g. L. acuminata. Typical form from Calcutta. 



h. Narrow form (?) of the same species from near Khulna in the Gangetio Delta. 



i. Type-specimen of L. mitnetica from the Inle Lake. 



The figures are not drawn to scale. Figs. E and F are after Clessin. 



shells of the narrowest type known to me — narrower even than the 

 var. gracilior, Marts. — both from the river Ganges and from the 



^ Dr. N. N. Marshall has recently sent me specimens of a small form of L. acuminata 

 from Rangoon. For good figures of the varieties of this species see von Martens, 

 Mitth. Conch.l, p. 75, pi. xiv (1886). 



