16 Proceedings. 



\Microscopical and Natural History Section^ 



Ordinary Meeting, November 5th, 1894. 



JOHN BOYD, Esq., President of the Section, in the Chair. 



Professor Weiss drew attention to the stem of the 

 melon, in which he had noticed an abnormal growth this 

 autumn — known as thyllosis — which tends in older plants 

 to fill the whole of the cavity of the tracheae and wide-pitted 

 vessels. The protrusions inwards arise from parenchy- 

 matous cells in contact with the vessels, and in the instance 

 of the melon these thyloses consisted of cells with spiral 

 thickenings. 



Mr. Charles Bailey, F.L.S., stated that a similar 

 growth occurred in the vine, as Professor van Heurck had 

 sent him a slide in 1 864, in which the large vessels of that 

 plant were filled with thyloses, and the compression of 

 growth had made them polyhedral in shape. 



Mr. J. COSMO Melvill, M.A., F.L.S., exhibited a shell, 

 Voluta aulica, found near the Philippine Islands, and des- 

 cribed as the most beautiful shell in the world. 



Mr. THOMAS Rogers exhibited some shells collected in 

 Egypt, of archaeological interest (Nerita, Cyprcza, Columbella) 

 of the period of the XXII. dynasty, about 900 years B.C., 

 several being perforated for use as ornaments. They were 

 found by Mr. Flinders Petrie ; also specimens of Nassa 

 out of Coptic tombs (Egypt), probable date 600 A.D. 



Mr. Charles Bailey exhibited a set of Swedish pond 

 weeds, just issued by Dr. Gustav Tiselius, entitled " Potamo- 

 getones Suecici exsiccati, Fasc. I. Nos. 1-50; 1894." He 

 pointed out that the southern portion of Sweden is studded 

 with fresh-water lakes and streams, which form a suitable 



