340 PROCEEDINGS OF THE 



structure than more solid bone. The " twelve punctures in one 

 line " of M'Coy are not distinctive. Strictly, there are two lines 

 of puncture-like spaces, one on each side of the cutting edge, 

 amounting in specimens under examination to 12 per ^o inch, 

 or 144 in each, in a tooth measuring fully an inch broad at the 

 widest part of the crown, or laterally, and three-fourths of an 

 inch long. 



III. — Kotes on the effects of Smohe on Vegetation, luith a list of Trees 

 and Shrubs specially adapted for planting in the neighbourhood of 

 large towns. By Mr Duncan M'Lellan, Superintendent of 

 Public Parks. 



It is almost unnecessary to say that smoke is injurious to 

 vegetation. In the neighbourhood of large towns and of chemical 

 works, for instance, where great quantities of smoke are daily 

 emitted, vegetation as a rule does not nearly come up to the usual 

 standard of nature. Tlie moisture which is so prevalent in our 

 northern climate does not help to alleviate this evil, but only 

 renders it worse, soot beino- much more liable to adhere to a wet 

 surface than to a dry one. Evergreens are more susceptible to 

 injury from this cause than deciduous trees and shrubs, which is 

 to be accounted for by the fact that their pores are constantly 

 exposed over the whole year to the sulphureous gases and smoke. 

 Deciduous trees, on the other hand, have the advantage of 

 throwing off their faded summer foliage, and of enjoying a rest of 

 several months, so that during that period, the worst of the year 

 for vegetation, they escape most of the injurious effects of smoke, 

 little or no sap circulating through the bark. In spring, as we 

 see at present, nature renews their suits of foliage, to be cast 

 aside when they have served their purpose. 



The varieties of deciduous trees and shrubs which are late of 

 bursting into leaf are those best suited for planting in towns. 

 The earlier sorts are liable to injury from the cutting east winds 

 which are prevalent in spring, and the foliage then being tender 

 cannot withstand the bad effects of smoke. The constitution of 

 the plants is thus impaired year by year, and they very soon 

 sicken off and die. Amongst evergreens the Coniferae or fir 

 tribe are the first to suffer from smoke, owing to the resinous 

 nature of their bark and spines, which retain almost every particle 

 of soot that falls upon them. Portugal laurels, Laurestinas, and 



