NATURAL HISTORY SOCIETY OF GLASGOW. XV 



up in the process of dredging the rivers for phosphates, and 

 consisted of teeth of a gigantic species of shark, bodies of ver- 

 tebrae of a whale, portion of a tusk of Mastodon, and fragments 

 of bones not capable of definite identification. The shark's 

 teeth were of great size and very perfect, the surface layers 

 being quite intact in all but two of the specimens, and the 

 serrations of the edges unbroken. From a comparison of these 

 with the plates and descriptions in Agassiz' Recherches sttr les 

 Poissons Fossiles, Mr. Clark was able to refer them to the 

 species Carcharodon Megatodon, although the specimens ex- 

 hibited exceeded in size any of those of which the measurements 

 were given by Agassiz. The largest measured 5 inches from 

 base to tip, and 4i inches in width at its widest part. If the 

 tooth bore the same relation to the length of the body that it 

 does in existing species, it might be assimied that the species to 

 which these teeth belonged were not less than 150 feet in length. 

 Mr. Clark, however, pointed out that a calculation such as this 

 must be regarded rather as an ingenious speculation than as an 

 ascertained fact, for it was not found that the relation referred 

 to was by any means constant or reliable. Specimens of such 

 teeth are to be found in many museums ; but it is rare to find 

 them quite perfect, and examples so large as those exhibited 

 are seldom met witli. 



Mr. Peter Cameron, Vice-President, exhibited a collection of 

 Ants made in the mountains of Ecuador by Mr. Edward 

 Whymper, the Alpine climber. The collection, which numbered 

 about 18 species, included several which are common in South 

 America; Caiiiponafus niarguiafu.s, Latr., found in North 

 America, Europe, and North Asia ; and Ponera carbonariay 

 Smith. Five or six of the species were apparently undescribed, 

 and among these was a remarkable new genus allied to Ponera 

 in the structure of the abdomen, but having the head not un- 

 like Criiptocerns. 



Mr. Cameron also exhibited the various forms of the South 

 American Foraging Ant (Ec'iton), and Leaf-cutting Ant (Atta), 

 and described the rem:irkable habits of these insects. The latter 

 is one of the most destructive insects in South America. It 

 destroys trees, especially the cultivated kinds, by denuding them 

 of their leaves, which are carried in small pieces by the ants to 

 their nests and there heaped up in masses. The ants do not 

 feed on the leaves themselves, but use them merely as a soil for 

 growing fungi, which appear to form their principal food. The 

 foraging ant, on the other hand, is rather a useful species, as it 

 feeds entirely on other insects. In certain districts immense 

 numbers of these ants invade the houses at particular seasons, 

 and thoroughly clear them of insects and other vermin. 



Mr. John Eenwick exhibited a number of Alpine Lichens 

 collected by him last September in the United States. He gave 



