iJO 



PROCEEDINGS OF THE ACADEMY OF 



I take the present opportunity of observing that yesterday, during: a stroll 

 in the meadows below the city, to procure specimens of the leech just de- 

 scribed, I observed that many of the ditches, and several ponds, were teeming 

 with the minute plant Wolffia, probably W. Columbiana, mingled with Lemna 

 polyrrhiza and L. minor. In several places I also observed Stentor polymorphic 

 swarming upon Ceratophyllum demersum, conspicuous by its bright pea-green 

 hue upon the darker hue of the latter plant. In similar positions I also ob- 

 served an abundance of Vo/vox globator. This latter I have frequently seen in 

 the vicinity of our city, and, preserved in an aquarium, have observed it pass 

 through the various stages representing what were formerly viewed as distinct 

 species under the names of V. aureus and V. stellatus. 



In the course of my walk, I noticed upon the margin of a ditch a large mass 

 of jelly, about two feet in breadth and about two inches in thickness, the 

 character of which I at first did not recognize. It reminded me of the jelly- 

 fish or medusa (Cyanea arclica), so frequently seen stranded on the ocean shore 

 of New Jersey. A nearer inspection proved it to be a mass of the remarkable 

 compound ciliated fresh-water polyp, or polyzoon, formerly described by me 

 under the name of Peclinatella magnified, which had, by an unusual recedeuce 

 of the tide, been left to die on shore. On examining the ditch in the vicinity, 

 I observed many masses of the same polyp, varying from the size of one's fist 

 to that of a boy's head, mostly attached to the pendent leaves of aquatic 

 plants growing at the margins of the ditch. 



Prof. Cope called attention to a large specimen of a Trigonocephalus, of 

 which some fourteen inches was enclosed in the oesophagus and stomach of a 

 larger Oxyrrhopus plumbeus. The specimens were from the island of St. Lucia, 

 W.I. He stated that a species not distantly related to the latter (Ophibolus 

 getulus) was said to have a similar habit of devouring our native Crotalidae. 

 The islands of Martinique and Guadaloupe had become so infested with the 

 fer-de-lance, Trigonocephaly lanceolatus, as to be in parts almost uninhabitable, 

 and that it was chiefly on account of the danger from this venomous reptile 

 that collecting naturalists had of late years so seldom visited them. The an- 

 nual number of deaths in Martinique from this cause was said to be very large. 

 Some means had been adopted to check the increase of this pest, but with 

 small results. Prof. Cope thought that as the Oxyrrhopus plumb eus was very 

 numerous in Venezuela and Brazil, and since it was very harmless and easily 

 procured, that its introduction in large numbers into Martinique, etc., would 

 be a simple matter, and one probably to be attended with good results in the 

 diminution, at least, of this enemy of agriculture. 



Mr. Thomas Meeiian called attention to the arrangements of some plants 

 for preventing fertilization through any other than insect agency, as dis- 

 covered by Darwin. The Salvia family of plants had the most elaborate 

 arrangements for insect agency, but it had been objected to Darwin's theory 

 that insects made no use of them. Bees bored holes through the tube from 

 the outside for the honey, and do not enter by the mouth of the flower, as 

 they ought. In the same way, in the Petunia, bees bore for honey from the 

 nnside. He had discovered that in these cases, where day insects failed to 

 make use of these apparatuses, fertilization was carried on by night moths, so 

 that the objections to Darwinism were removed. 



He also referred to the common sweet chestnut, as bearing two classes of 

 male flowers, only one of which probably aided in fertilization. The first , 

 class appeared ten days before the other, and are those which give whiteness 

 to the trees. They appear in the axils of the weak shoots. The female flowers 

 appear on the apices of strong shoots, according to his theory of the laws of 

 sex. The second class of male flowers appear at the ends of the vigorous 

 shoots bearing the female flowers. Whatever affects the vigor of the tree in- 

 terferes with the production of female but not, of male flowers, and this was 

 the reason why some seasons had short crops. 



[Aug. 



