322 PROCEEDINGS OF THE 



by Don, in Clova, though this has not been confirmed. Oxalis 

 corniculata finds a place in the Clydesdale flora, the authority 

 being Hopkirk, who gives Barncluith as its station, but it has not 

 been found by any one else. There were other species in the 

 collection which, although not so noteworthy as the foregoing, 

 are by no means common here, such as MeUlotiis officinalis, 

 Sagittaria sagiUifoUa, Lonicera ccqjrifolium, Cynoglossum officinale, 

 Lycopodium annotinum, etc. There were also a number of speci- 

 mens belonging to orders which are unknown here, and others 

 of genera corresponding to ours, but of species of which we 

 have no representative, and which have no recognised place 

 in our lists. Among these were fine specimens of AcVmntum 

 peclatum, belonging to a genus only found in warm or sub-tropical 

 countries. Adiantum Cainllus- Veneris is the only one out of 62 

 species that is found in Britain, and that only in the southern 

 counties. Canada, which is in a lower latitude than the British 

 islands, has a more rigid winter, but in summer the heat is almost 

 tropical, and Adiantum pedatum is as common in the woods and 

 fields as the grasses are with us. 



PAPERS READ. 



I. — Ou CUtonellus, recent and fossil. By Mr John Young, F.G.S. 



Mr Youna; stated that in the valuable collection of natural 

 history objects recently presented by Dr Allen Thomson to the 

 Hunterian Museum, he was much gratified to find a fine specimen 

 of a recent Chitonellus j^reserved in spirit^, which showed in a 

 very satisfactory manner the arrangement of the eight plates which 

 are inserted in the mantle of the animal. Chitonellus forms a sub- 

 genus of the Chitonidae, a family of molluscs, in which the shell 

 is composed of eight imbricating plates, inserted in an overlapping 

 series in the coriaceous mantle by means of projecting processes 

 on the plates termed apophyses. The plates in the various species 

 of Chitons diff'er considerably in form, as well as in their external 

 sculpturing, and these differences constitute the distinctions 

 between the several sub-genera and species. Of the true Chitons 

 more than two hundred and fifty living species are known, and 

 they are found in all seas throughout the world, ranging from the 

 rocks at low water to depths of from 10 to 25 fathoms; but, 

 according to Professor E. Forbes, some of the British species are 

 found at a depth of 100 fathoms. The fiimily of the Chitonidae 



