TRANSACTIONS OF SECTION C. 643 



2. The Investigation of Fossil Remains by Serial Sections. 

 By Professor W. J. Sollas, Z^.aS'c, F.R.S. 



It is now becoming increasingly recognised that the key to the evohition of 

 the animal kingdom is not the exclusive possession of ontogeny alone, but is shared 

 at least equally by the sister science palpeontology. The information afforded by 

 the latter study is far less than might be justly expected, owing to the insuf- 

 ficiency of its methods. The method of fossil sections has worked a revolution 

 in zoology since its tirst introduction some few decades ago. Could it be applied 

 to fossils no less far-reaching results would naturally follow in paheontology. 

 Serial thin sections for examination by transmitted light are, however, in 

 most eases out of the question, since they cannot be obtained in a sufficiently 

 close succession. The same objection, however, does not apply to polished 

 surfaces intended for observation under the microscope by reflected light. 



These can be obtained to almost any desii'ed degree of proximity, and a 

 grinding machine designed for the author by the Rev. Gervase Smith, and 

 constructed with the aid of a grant from the Eoyal Society, furnishes a series 

 of parallel plane surfaces at regular intervals of from 01 to O'O.S mm. In the 

 case of fairly well preserved specimens these may be studied under powers of from 

 1 inch to ^ inch, and all the details of their anatomy ascertained. 



Drawings under the camera lucida or photographs may be obtained from 

 them, and from a series of such drawings the fossil may be reconstructed on an 

 enlarged scale. Already several species of fossils have been treated in this way 

 with complete success. Supplemented by a few thin transparent sections it 

 aflfords a means for ascertaining the anatomy of fossils in fulness and with 

 precision. 



The 80-called Ophiiira Egertojn, which the author has studied in conjunction 

 with 3Iiss F. Wright, displays under the method of grinding all those minute 

 characters on which zoologists depend for the determination of recent species, 

 including the tentacle scales, teeth, buccal papillse, and the granulations on the 

 buccal plates. The details of the anatomy of LapwortJiura Miltoni are also clearly 

 revealed, and in both cases the anatomy of the jaws is so exactly indicated that 

 from these fossil remains alone the homology of these organs can be ascertained. 



Models were exhibited prepared from serial sections of Palceospondiilus Giinni, 

 Traquair, taken in longitudinal, transverse, and facial directions. These were 

 obtained and studied by Miss Igerna Sollas and the author. They appear to 

 reveal the existence of a dorsal shield, a maxillary arch, a palatine element, and 

 a suspensorium, as well as gill arches. A lower jaw is indicated. While pointing 

 in some directions to the Cyclostomes the more important characters of the 

 fossil suggest affinities with the Amphibia and Dipnoi. 



Models in wax have also been prepared of Monoyrcqytus priodon, and were 

 exhibited before the Section. 



3. Notes on some Fossil Plants from Berwickshire. By E. Kidstojt. 



4. Report on Life-zones in the British Carboniferous Rocks. 

 See Reports, p. 288. 



5. Geology regarded in its Economic Application to Agricidture by Means 

 of Soil Maps. By J. R. Kilroe. 



It is proposed to consider the means by which geological information can best 

 be applied to agriculture, the utility of the application being assumed to be univer- 

 sally admitted. 



Amongst the objects to be aimed at should be the furnishing of reasons and 

 suggestions for the protitable localisation of certain branches of the industry, viz., 



