152 



Botanical Society of Edinburgh. 



self had been disposed to consider it a variety of Hypnum cirrhosum. 

 Mr. Wilson had, however, satisfied him that it could scarcely be so 

 considered. In the absence of fructification, Mr. Wilson preferred 

 to regard it as a variety of Leucodon Lagurus (although there were 

 certainly some differences of character) rather than unnecessarily to 

 multiply species. Dr. Greville was still disposed, on the strength of 

 the great difference in habit, to doubt of its claim to the place assigned 

 to it, and thought it probable that the fructification, when discovered, 

 would remove it altogether from Leucodon. 



The following papers were read : — 



1 . "On the Structure of Diatomacese," by E. W. Dallas, F.R.S.E. 



The author directed attention to the list of species which follows, 

 and which, although imperfect, exhibits great variety in the forms, 

 showing the Medway to be very fertile in these organisms. 



Epithemia Museums. 

 Campylodiscus cribrosus. 

 Surirella striatula. 



Nitzschia sigmoidea. 

 dubia. 



linearis. 



Tryblionella marginata, 



Scutellum. 



punctata. 



gracilis. 



acuminata. 



Cymatopleura elliptica. 

 Triceratium Favus. 



striolatum. 



undulatum. 



Cyclotella Kiitzingiana, 



operculata. 



And three species undetermined. 

 Actinocyclus undulatus. 



senarius. 



septenarius. 



octonarius. 



nonarius. 



Eupodiscus Argus, 2 vars. 



radiatus. 



maculatus. 



Coscinodiscus radiatus. 



minor. 



cccentricus. 



Thwaitesii. 



And an undetermined species. 

 Navicula elliptica. 



convexa. 



Westii (?). 



didyma. 



pusilla. 



punctulata. 



palpebralis. 



Pinnularia divergens. 

 Stauroneis pulchella. 

 Cocconema parvum. 

 Pleurosigma balticum. 



Hippocampus. 



angulatum. 



acuminatum. 



distortum. 



Doryphora Amphiceros, vars. 



Boeckii. 



Achnanthes brevipes. 

 Grammatophora marina (?). 

 Biddulphia aurita. 

 Zygoceros rhombus. 

 Dentricella sp. 

 Orthoseira sp. 

 Dictyocha. 

 Bacteriastrum furcatum (?). 



curvatum (?). 



And an undetermined species. 

 Cocconeis Pediculus. 

 Scutellum. 



Some of the species in the foregoing list have been described as 

 new to Britain, by Mr. Roper in a paper recently published in the 

 ' Microscopical Journal.' The Coscinodiscus, not named, seems from 

 the description to be the same with that found at the mouth of the 

 Thames, and is an exceedingly beautiful disc. The four species of 



