166 Royal Society : — 



The secretiou-cells are subjected to the creative activity of 

 a composite organism, the preservation and regeneration of 

 which they subserve ; their task is synthesis. On the con- 

 ti-ary it is the office of these ferments to decompose dead and 

 dying organic substances into their simpler compounds, and 

 to prepare them for decay ; their task is analysis. To regard 

 these ferment-cells [Hysteropliymata) as equivalent to perfect 

 organisms shows a complete misconception of their true nature. 

 Schaffhausen, November 1873. 



PROCEEDINGS OF LEARNED SOCIETIES. 



EOYAL SOCIETY. 



May 8, 1873. — Francis Sibson, M.D., Vice-President, iii the Chair. 



" Contributions to the Study of the Errant Auuelides of the 

 Older Palaeozoic Eocks." Bv H. Alley>'e Nicholson, M.D., 

 D.Sc, M.A,, Ph.D., F.E.S.E., Professor of Natural History in 

 University College, Toronto. 



In this communication the author endeavours to elucidate the 

 abuudaut and obscure organic remains which are found so com- 

 monly in the Pala'ozoic rocks, and especially in the Silurian strata 

 of Britain, and uhich are generally known by the vague and con- 

 venient names of " Fucoids,"' " Annehde-burrows," and " tracks." 

 After expressing his opinion that the first step towards the study 

 of these obscure fossds hes in the pro^-isioual grouping and naming 

 of the more marked fonns which are already known to exist, the 

 author proceeds to divide the remains under consideration into 

 two great groups. In the first of these groups are those fossils 

 which are truly the huj-rows of marine worms, as distinguished from 

 mere trails and surface-tracks. Some of these burrows (ScoUthus) 

 are more or less nearly vertical in direction as regards the strata 

 in which they are found ; and they are to be looked upon as being 

 true burrows of habitation. lu this section are placed the genera 

 ScoUthus, ArenicoUtes, and Ilistioderma. Other burrows are of a 

 totally difi:erent nature from the preceding, and \n?bj reasonably be 

 compared to the bu^^o^^'s of the recent lobworms. These burrows 

 run more or less horizontally as compared vdih the laminse of depo- 

 sition, or they penetrate the strata obhquely. They are not bur- 

 rows of habitation, but are wandering tunnels exca\ated by the 

 worm in its search after food. The fossils of this group, there- 

 fore, as preserved to us, are not the actual burrows themselves, 

 but the burrows filled up M-ith the sand or mud which the worm 

 has passed through its ahmeutary canal. The burrows of this 

 kind (including many forms previously described under the names 



