138 ORGANISMS FROM THE RECENTLY-DISCOVERED 



the oi)erculum, which is peculiar in having on its under side a 

 projection, which seems to keep it in a proper position. The 

 shell is prettily marked with purple bands, and the broad cha- 

 racter of the inner lip is very noticeable. This mollusc inhabits 

 rivers and lakes. The female deposits her capsules, containing from 

 forty-five to sixty eggs, upon the shells of neighbouring molluscs. 

 In the second family of this order, Fahidinidce, most of the shells 

 in the deposit are found to belong to Genus 2, Bythmia, species 

 BJeiitacidata. In the living creature the tentacles are filiform, and 

 the shells, when thoroughly cleansed, are beautifully transparent. 

 The deposit is full of their opercula which have become sepa- 

 rated from the shells, and in themselves are very pretty with their 

 concentric markings, being, in fact, plates of growth in different 

 stages of the creature's existence, deposited one over another. 

 This mollusc is very common and very timid, retreating into its 

 shell with the slightest touch. It floats under the water, and 

 deposits its eggs, 10 to 70 in number, on stones or on aquatic 

 plants. In the third family, Valvatidce^ no specimen is found in 

 my collection. 



In the second order, Pulmonobranchiata^ there is a large 

 number of specimens from the family Limiiccidcc. In the first 

 genus, Planorhis^ Mr. Rimmer has named for me the small and 

 really microscopic species, P. naiitileus. I think it is the gem 

 of the collection when viewed under a low power, its markings 

 bearing a striking resemblance to the beautiful curves and ridges 

 of the well-known Nautilus which have originated its specific 

 name. Another species of this family, in my collecdon, is P. 

 co/nplanattcs, a discoid shell of much larger size. Both species are 

 shy and irritable, attaching themselves to aquatic plants, and 

 dropping from their attachments instantly if touched, retreating 

 at the same time safely within their shells, which are considerably 

 larger than the body of the animal they protect. 



In the third genus, Liiiuuca^ Mr. Rimmer has named for me 

 Z. pC7rgra, a species found very abundantly in the collection, 

 both in its young and mature stages. This mollusc inhabits ponds 

 and ditches, climbing the stems and leaves of plants above water- 

 mark, and is fond of wandering. It is also very predatory, 

 and has been known to attack and eat minnows, and even other 



