•o Proceedings or the 



8ir Nicolas YekiMoloit, K.C.B., K.C.V.O., T.L.S., read his 

 " Notes on Cliivloceros iiiiil iillied generii, living: and fossil," witli 

 laiiteni-slides, of which the t'ollo\viij<r is an abstract : — 



The J)iat()in i^enus CJidtoceros sliows sevenil pecuHar features. 

 Jt has been hi;;lily differentiated for pelagic life. It occurs in the 

 planktons of ihe colder seas, sonietinies, es|)ecia]ly in spring, in 

 colossal nunihers. Wonie 100 living sjx'cies have been described, 

 but only (! or 7 are coninion in the ]ilanktons. 



'I'he parent ceils, each consisting of two valves with a hoop 

 between I hem, form colonies, holding together by means of long 

 setsB. The \\ hole structure of the colony endow s it with great 

 floating capacity. 



Two features of the genus are especially puzzling: one is that 

 several of the species, though not all, have the capacity to develop 

 inside the mother-cells peculiar internal organs, covered with a 

 thick siliceous wall. These organs, rightly or wrongly, are called 

 slntojiores. No one has ever seen tliem germinate, and whether 

 they ai'e organs of I'eproduction, or something like endocysts, or 

 something else, is not known. 



The other strange feature of the genus is, that although it is so 

 infinitely numerous in the planktons, nevertheless the mother- 

 cells, or colonies, as such, never appear in any fossil marine 

 deposits. On the other hand, the spores do appear fairly often 

 as fossil remains. Why it is that the vegetative form cannot 

 stand fossilization whilst the spore can do so, is not known. 



Although the spores of Cha'toceros are all built on very similar 

 lines, yet the elder authors, since Ehrenberg, have taken them for 

 separate Diatom genera, and have classified and named them as 

 such. Thus some five new Diatom genera have been created. Of 

 them, three (Synch)} drium Ehr., Dicladia Ehr., and Hercotheca Ehr.) 

 are undoubtedly spores of Ohcetoceros. Two other genera (Gonio- 

 thecinm Ehr. and Xanthiopyxis Ehr.) may or may not be spores of 

 Ohcetoceros, or of some other form yec unknown. 



Fossil spores of Chcetovet-os are to be found frequently enough in 

 Miocene Diatomaceous earths. The most common form is Si/nclen- 

 clrium Ehr., which is the spore of Chcelocn'os cUadema Gran, very 

 common in the planktons. 



Dr. Clarence Tierney (visitor) contributed further remarks, and 

 the author replied. 



Mr. HuBEifT Ltman Clapjc's paper, "Some Echinoderms from 

 West Australia," commuiiicated by Prof. W. J. Dakin, F.L.S., was, 

 in the absence of the author, read in title. 



Miss K.AT11BONE, F.L.S., brought for exhibition W. Gardiner's 

 ' Musci britannici,' Glasgow, 1836, 8", with specimens of the 

 mosses ; this seems to have been the earliest issue, followed after- 

 wards by the Dundee and London editions. 



