NATURAL HISTORY SOCIETY OF GLASGOW. 29 



present. To give some idea of the work devolving on a Crinoid, 

 consequent on the attachment of this coral, the following measure- 

 ments of the two largest specimens which have come under my 

 notice (in the British Museum) may be taken : — The original stem 

 at the point measured was five lines in diameter: as now seen, with 

 the additional secreted matter surrounding the Cladochoniis, the 

 diameter is one inch five lines, and the circumference four inches 

 seven lines. Another almost equally large stem originally 

 measured four lines — in its present state the diameter is one inch 

 one line, and the circumference three inches eleven lines. There 

 is in this specimen one of the ordinary circular apertures which 

 lead directly into the calice of a C'laclochonus. 



It is a curious fact that most of the examples which have come 

 under my observation from Derbyshire or Yorkshire are caused by 

 Cladochonus, although there are a few good specimens of the 

 passage leading direct to the columnar canal from these localities, 

 in the British Museum (PL II. figs. 1 and 6). I have not suc- 

 ceeded in obtaining any clear evidence of enlarged Crinoid stems, 

 arising from this cause, occurring in Scotch Carboniferous beds, 

 although there is no reason why they should not, as Cladochonus 

 occurs plentifully at certain localities. 



Before closing this portion of our inquiry, it may perhaps be well 

 to refer to some peculiar specimens also in the British Museum 

 Collection (PI. II. figs. 16 and 17), but which diner greatly in 

 appearance from the true C ladochonas-hif ested stems. Those 

 now under consideration have the whole surface riddled with 

 circular holes, without showing any signs of enlargement. The 

 apertures are arranged roughly in cycles, apparently following the 

 line of demarcation between the ossicles composing the stem, and 

 vary much in size. When very prevalent and close together they 

 impart to the Crinoidal column a bitten and decayed appearance, 

 changing its whole aspect. In some instances, wdiere less weathered, 

 one of the margins appears to project more than the others. So far, 

 sections have not revealed any satisfactory solution of this peculiar 

 appearance, for the apertures do not appear to lead any distance 

 into the stem, but are merely superficial. 



2. Favosites parasitica (Phillips)— The Bofe Collection (British 

 Museum) contains a Crinoid stem, with a colony of this coral 

 attached, occupying a central position on the stem, the latter 

 having become swollen above and below it, thus leaving the 



