Vi PROCEEDINGS OF THE 



being the most suitable. The sections, after having been 

 soaked in this sokition for a night, should then be immersed 

 for about twenty minutes in a solution of carmine. When 

 removed from the carmine they should be thoroughly washed — 

 first with water, to which a few drops of acid had been added, 

 to neutralise the ammonia, and afterwards with pure water. 

 At this stage they would have acquired a bright pink colour. 

 They should then be dyed in an aniline dye, " iodine-green " 

 being most suitable, in the proportion of three grains to an 

 ounce of alcohol. In this solution the sections should remain 

 for a night, and afterwards be washed in absolute alcohol for a 

 minute or so, according to circumstances. They should next be 

 immersed in oil of cloves, in which they would acquire perfect 

 transparency, and might then be mounted with a solution of 

 balsam in benzine. In illustration of the process which he had 

 described, Mr. Goodwin exhibited under the microscope several 

 slides prepared in the manner indicated. 



14th August, 1883. 



Mr. George R. Alexander in the Chair. 



Mr. Joseph Sommerville reported that an excursion had been 

 made on 8th inst. to the Forth and Clyde Canal at Port-Dun- 

 das and Firhill Timber-basins. Fresh- water Sponges (Spongillcv) 

 were found adhering to the timber-logs, several aquatic mol- 

 luscs were collected, and the three rarer species of Duckweed 

 (Letnna trisulca, L., L. gibbet, L., and L. jyolijrhiza, L.) were 

 obtained. Mr. Sommerville exhibited a Spongilla which had 

 been washed with weak acid so as to leave exposed the skele- 

 ton of white, siliceous spicules. 



Mr. James Steel submitted the following list of Fresh-water 

 3Iollusca observed in the Timber-basins, viz. : 

 Sphceriuvi corneiun, L. — Common. 



Dreissena x>olyinorplia, Pallas.— Common, and found in all 



stages of growth from the 

 fry upwards. This shell, 

 which occurs as an upper 

 tertiary fossil in the north 

 of France, was not observed 

 in Britain till 1824. Dr. 

 J*eifries is inclined to regai-d 

 the species as indigenous. 

 Bythinia te7itaculatci, L. — Common. - 



Valvata piscinalis, Miill.— Frequent. Remarkable for the 



feather-like branchial appendages. 

 Planorhis albus, Miill.— Common. 



