8*2 7'rfi iixfirf'ions. 



all built up on the same principle, although they may be of 

 diliei'ent size and outline. The model shown is of the Graptolite 

 (Monographis jyriodon), enlarged about 30 diameters. It may be 

 either straight or curved, with a solid axis or stipe, upon which 

 the polypery is built. The common canal is well mai'ked, in 

 which was contained tlie ca^nosarc, from which each polyp was 

 developed. On tlie margin of the periderm whicli surrounds tlie 

 cajnosarc, the hydrothecM or cells are constructed, eacli individual 

 polyp going througli the caenosarc to the subsistence of the whole 

 colony. The whole of the outside of the polypery is composed of 

 a chitinous or liorny substance, generally in the course of 

 mineralisation, the mouth of the cellule being at the point of the 

 denticle, each cell being inhabited by a polyp, and having com- 

 munication with the common canal. The simple Monograptus is 

 supposed to have four margins or borders surrounding a hollow 

 tube, the inner resting on the common canal, which is not 

 defined, tlie superior on the top, or point on which is the cell 

 mouth. This description applies to nearly all tlie other simple 

 forms of graptolites. In collecting the above organisms I think 

 it is a matter of much importance to procure, if possible, those 

 fossils with both their distal and initial points, as they can be 

 identified with greater certainty, besides rendering the forms of 

 the organisms more complete. 



III. A Memoir of the Rev. Mr Gatt, Minister of Graitney, 1727-87. 

 By Mr J. Gibson H. Starke, Vice-President. 



The subject of this short notice — the Rev. James Gatt — seems 

 to me worthy of having his name recorded in the proceedings of 

 this Society, as an eminent pai'ish minister in Dumfriesshire who, 

 during his lifetime, was probably as widely known as any among 

 his contemporaries ; and whose memory still lingers among a few 

 of the present generation. No formal biography of him has ever 

 been published, and it is now impossible to obtain sufficient 

 materials for this purpose, but from two brief notices of him 

 which have been published, and from traditionary accounts, he 

 was not only beloved as a minister, but eminent as a scholar. 



The leading events of his life are given in the Fasti Ecclesioi 

 Scoticawf, by Dr Hew Scott ; and an appreciative sketch of his 

 character appeared in " Good Words " for December, 1876, by 

 the Rev. Mr Edgar, formerly minister of Graitney, or, as it is now 



