Zoological Society. 379 



would have entirely disappeared, but for the assistance of a 

 watchman, whom I engaged to supply water at intervals. At 

 a maximum, I suppose the mass of ice was at times about two 

 inches square, and from a quarter to a half an inch thick. 

 The gradual introduction of the water, by aid of the funnel 

 and valve cock, also of a pipe by which it was conducted to 

 the cavity in the sheet brass, enabled me to accumulate a much 

 larger mass than I could have procured otherwise. A brass 

 band embracing the inner jar near the brim, with the three 

 straps proceeding from it, serves to keep this jar in a proper 

 position; that is, in fact, concentric with the outer jar. 



In this last-mentioned experiment, I employed an air-pump 

 upon a new construction, which I have lately contrived, and 

 of which I shall soon publish a description. 



LV. Proceedings of Learned Societies. 



ZOOLOGICAL SOCIETY. 



1834*. A LETTER was read addressed to the Secretary by 

 July 8.— <£*- M. Julien Desjardins, Corr. Memb. Z.S., dated 

 Mauritius, January 10, 1834. It accompanied a collection of ob- 

 jects of Zoology, consisting chiefly of Mammalia and Birds, which 

 were exhibited to the Meeting. 



Mr. Gray exhibited various undescribed Shells, chiefly contained 

 in his own collection. He characterized them as Unio Novcb Hoi- 

 landice, and Anodon Parishii, penicillatus, and porcifer; the cha- 

 racters of each species being given in the Society's " Proceedings." 



Mr. Gray also exhibited specimens of several Shells, which he 

 referred to a genus to be separated from Helix under the name of 

 Nanina. Helix (pars), Fer. Vitrina (pars,) Quoy. Animal. Col- 

 lare amplum, lobo dextro antico, antro respirationis in sinu posito, 

 lobo sinistro postico lato expanso partem inferiorem testae anfractus 

 ultimi tegente. Pes postice truncatus, processu brevi conico dor- 

 sali supra truncaturam sito. Testa depressa, perforata, polita ; 

 apertura lunata ; peristomate tenui, edentulo, costa interna vel 

 nulla vel obsoleta. India, Chinee, fyc. lncolce. 



The shells comprised in this genus have been referred by M. De 

 Ferussac, and by most authors, to Helix : they are, however, more 

 nearly related to Vitrina, with which M. Quoy intends placing them. 

 But from the shell of Vitrina that of Nanina differs by being um- 

 bilicated, as well as by its smaller mouth. The lobation of the collar 

 of the animal of Nanina distinguishes it also from Vitrina ; the 

 collar of the latter being entire, with a linear lobe on the side ex- 

 tending over the shell, and with the respiratory hole placed at its 

 base. 



3 C 2 



