116 PROCEEDINGS OF THE ACABEMY OP 



The last tooth, the smallest of those in the jaw specimen, was 

 also inserted by a pair of fangs. Its crown is broken away. 



The animal indicated by the jaw fragment appears to liaA'e held 

 a position intermediate to the musteline and canine families. It 

 was proposed to name it Sinopa rapax, the former name, ac- 

 cording to Prof. Hayden, being that applied by the Blackfeet 

 Indians to a small Fox. 



Mr. Thomas Meehan exhibited a specimen of Achillea mille- 

 folium, in which an underground stolon of an Agrostis had pene- 

 trated, and referred to a similar case, to which he had called the 

 attention of members last year, where a Triticum had penetrated 

 through large tubers of potatoes. He remarked at that time on the 

 peculiarity of the growing force of plants which would rather en- 

 deavor to push directl}^ through an obstruction, than turn to one 

 side out of its straight course. He thought the present instance still 

 more remarkable, as the living stem of Achillea was little thicker 

 than ordinary brown thread, ^^et the grass had cloven it directly 

 in halves in a manner we could scared}^ imitate with a needle. 



He then presented a quantity of sprouting peach-kernels, in 

 order to call attention to the great variety of form which existed 

 in the cotyledons. The most usual was ovate, the apex and base 

 both regularly tapering, but some were obtuse — occasionally 

 almost square — at the apex ; while others were so lengthened out 

 at the base as to give to the cotyledon a spathulate form. Others 

 were cordate at the base, some more with the base of the lobes 

 spurred, and others again which were simply gibbous on one side. 

 We were, he said, all familiar enough with the fact of great natural 

 variations in foliar and floral organs, but he believed no great 

 differences in cotyledons have been exhibited here. 



But he thought there prevailed a still greater interest in the 

 lobing of the separate cot^dedons. It was very common to find 

 some which had one of the cotyledons separated for one-third the 

 depth, some one-half, and occasionally two-thirds, and in some 

 cases both cotjdedons would be divided, so as to present the ap- 

 pearance of four perfect ones — that is, the two would be divided 

 almost down to what might be termed their petioles. Still more 

 intei'esting he thought the fact that, in one of the cases he exhibited, 

 another plumula had been formed in the angle of the divided coty- 

 ledons. It had been his opinion that in many plants cotyledons 

 were to be considered as modified axis, rather than modified leaf, 

 speaking according to the general idea of stem-structure, for he 

 inclined to the opinion that all axis originallj' is but modified 

 leaf — and in these cases it would seem as if the cotyledons had 

 started to make anotlier mode of growth, as a true stem axis 

 would do. 



In regard to the number of cotyledons, he thought a close ex- 

 amination might find it variable in many classes of plants. Mr. 

 Burk, of the Academy, liad called his attention to the fact that it 



[July 11, 



