NATURAL SCIENCES OF PHILADELPHIA. 183 



Mr. Gabb made some remarks on a small lot of fossils submitted to him by- 

 Prof. Orton. The fossils are small, and all belong to undescribed species. 

 They are of unusual interest, being the first fossils, so far as he was aware, 

 ever found in the immense clay deposits of the Amazon Valley — the Tabatingu 

 Clay. The fossils indicate a marine origin for this clay, all of the genera being 

 essentially salt-water forms. They were found by Prof. Orton in a bluff show- 

 ing a fine section of about fifty feet in height, at the town of Pebas, on the 

 Amazon River, two miles above where it joins the Maranon. 



July 28th. 

 Dr. J. Gibbons Hunt in the Chair. 

 Fifteen members present. 



The following gentlemen were elected members : Geo. Roberts, 

 M.D., Mr. Levi Taylor. 



The following were elected correspondents : S. Spencer Cobbold, 

 M.D., of London, W. Kitchen Parker, of London, Rev. Samuel 

 Haughton, of Dublin, Alphouse Milue Edwards, of Paris, Wm. T. 

 Brigham, of Boston. 



On favorable reports of the committees, the following papers 

 were ordered to be printed : 



MITCHELLA REFEITS, L., a dioecious plant. 

 BY THOMAS MEEHAN. 



A few weeks ago I had the honor of pointing out to the members of the 

 Academy that Epigxa repens was a dioecious plant. I have now to report a 

 like discovery in 3Iitchella repens. 



In the case of Epiycea I had to indicate the polymorphism accompanying 

 the divisions of the sexes, as part of the discovery ; in the present instance 

 Dr. Asa Gray is before me in noting the distinct appearances ; the originality 

 of my own observation lies merely in giving the meaning of the facts already 

 recorded. In the last (5th) edition of Gray's Alanual, speaking of Mttchella, 

 the author says, "Flowers occasionally 3 — 6, merous, always dimorphous, all 

 those of some individuals having exserted stamens and included stigmas, — of 

 others included stamens and exserted style." Although this statement ex- 

 presses the appenrance, it is not strictly accurate ; for the pistil in the one 

 case is not perfect, and in the other the anthers are mere rudiments, without 

 a trace of pollen in any that I have examined, The two forms are truly male 

 and female plants. 



In the female plant the pistil, with its well-developed stigma, projects 

 one-eighth of an inch beyond the throat of the corolla. The small rudiment- 

 ary anthers are sessile, and hidden among the coarse down of the corolla 

 tube, so as not to be seen without dissection. 



In the male plant it is the rudimentary pistil which is confined in the 

 villous tube, far out of reach of pollen iufiuence, if even it were perfectly de- 

 veloped. On the other hand, the anthers are borne on filaments which are 

 free from the corolla for one-eighth of an inch, and projecting that much 

 beyond the corolla throat. 



In the case of Epigxal had to record many variations in the form and pro- 

 portions of the floral parts. Mitchella is as remarkable for unifojynity ; except 

 that the calyx teeth in the male are coarser than in the female, there is little 

 variation from one type. Dr. Gray observes that the lobes of the corolla 



1868.] 



