80 PROCEEDINGS OF THE ACADEMY OP 



testicle. I take the opportunit}'' of acknowledging the assistance 

 afforded me in m^"^ dissection by Dr. Leidy's beautiful monograph 

 on the Gasteropoda. 



May 19. 



Dr. Kenderdine in the chair. 

 Twenty-five members present. 



The Veins of Beech and Hornbean Leaves. Mr. Thomas Mee- 

 HAN said that De Candolle had noticed some years since a differ- 

 ence in the venation between the Fagus ferruginea and Fagus 

 sylvatico., the common American and European beeches. In the 

 American beech the lateral veins were said to terminate in the 

 apex of the serratures in the European they terminate at the base 

 of the sinus. He had not read the original paper of De Candolle, 

 but abstracts in the scientific serials. As the statement stood, it 

 conveyed the idea that there was a marked difference in structure 

 between these two allied species which did not, however, exist, as 

 groM'ing in this countr}'^ the leaves of the European beecli are al- 

 most entire ; the lateral veins, in approaching the margin of the 

 leaves, curve upwards, and connect with the lateral above tliem, 

 forming a sort of marginal vein near the outer edge of the leaf. 

 The veins of the American beech curve upward in the same way, 

 biTt are early arrested, and this sudden cessation of growth pro- 

 duces the serra, which are slightly curved upwards. An early ar- 

 restation of growth in the veins makes the serratures, and consti- 

 tutes the onl}^ difference between the two species. The structural 

 plan is the same in both the European, curving its lateral vein 

 into the apex, reached the upper one the American terminating 

 abruptly. 



There was a greater tendency to marginal development in some 

 European than in allied American species. In the Garpinus Be- 

 tulus, the English Hornbean, there were from four to five teeth 

 between each pair of lateral nerves, while there were but from two 

 to three between those of the American Garpinus Americana 

 a character that was quite as distinctive between these two very 

 closely allied species, as the viens were in the case of the beech. 



Direct Growth Force. Mr, Meehan referred to some potatoes 

 exhibited by him to the Academy a few years ago, in which the 

 stolons of a grass had penetrated througli from one side to the 

 other, preferring, as it would seem, to go through such an ob- 

 struction to turning aside to avoid it. A potato was a rather 

 rough surfaced body. He now exhibited a similar case, only the 

 obstruction was the round smooth root of an herbaceous peony. 

 Though not more than one-third of an inch thick and round, a 



