NATURAL HISTORY SOCIETY OF GLASGOW. 155 



leaves, formerly regarded by botanists as belonging to Asterophyl- 

 liies or Annidaria. Mr Young stated that the remains of Calamites 

 were abundant in the roof shales of many localities in the Lanark- 

 shire coalfield, but that it rarely happened that any of the foliage 

 of the plant was found attached to the stems; the specimen 

 exhibited being the only example he had ever met with, although 

 examples had been found elsewhere in British Carboniferous 

 strata. Mr Young next referred to the class of plants to which 

 the extinct family of the Calamites were most nearly related, viz., 

 the recent Eqidsetaceae, or Horse-tails, found in our marshes, of 

 which the fossil Calamites were the gigantic progenitors. Eecent 

 discoveries of the stems of Calamites in the coal measures, with 

 portions of the foliage attached, have proved that the plants with 

 whorled leaves, formerly referred to the genera Asferojyhyllites, 

 Annularia, and SjjJienophyUum, were the foliage of various species 

 of Calamites, and that the genera Volkmn.nnia and Pinmdaria of 

 which he exhibited specimens, were their fruits and roots — these 

 facts being established on the evidence of the more perfect 

 specimens found, and the better knowledge now obtained of 

 the relation and affinities of the plants of our coal measures. 



Professor Dickson exhibited specimens illustrating some of the 

 principal spirals found in Fir Cones. He stated that in these, as 

 in the higher plants generally, the spiral arrangements fall under 

 one or other of the terms of the series of fractions ^, ^, -|, |-, etc. 

 Exceptional cases, however, are met with not very unfrequently, 

 where, either what are termed conjugate spirals {i.e., two or more 

 parallel spirals resulting from opposite or whorled leaves or scales) 

 occur, or where there is a single spiral not belonging to the 

 normal series. For example, in the common Spruce Fir about 

 95 per cent, of the cones exhibit an -f-^^- arrangement — a spiral 

 belonging to the ordinary system : the remaining 5 per cent, being 

 exceptional, and consisting sometimes of a bijugate spiral, where 

 the angular divergence in each of the two parallel spirals is 

 oi ^ o , (=ot) of the circumference; sometimes of a ~ spiral, a 

 term of the series ^, -J, |, 3^, -j^, etc; and more rarely of a 

 trijugate spiral, where the divergences of each of the three parallel 

 spirals = T3"V^' - A- The per centage of abnormalities seems 

 to vary to some extent with the individual tree, — and is higher 

 in some species than in others — thus, in Pimis pinaster at any 



