NATURAL SCIENCES OF PHILADELPHIA. 147 



Birds collected at Laredo, Texas, in 1866 and 1867." By Dr. H. 

 B. Butcher. 



May 12th. 

 Mr. Vaux, Vice-President, in the Chair. 



Thirty-six members present. 



The following were presented for publication : " Description of 

 Four new species of Exotic Unionidre," and " Description of Twen- 

 ty-six new species of Melanidse of the United States." By Isaac 

 Lea, LL.D. 



" Monoecism in Luzula campestris," and " Variations in Epigea 

 repens." By Thos. Meehan. 



Prof. Edw. D. Cope defined the characters of a new genus of Cheloniidae, 

 which re{>resented the modern marine turtles in the Cretaceous green sand of 

 New Jersey. It differed in the considerably greater co-ossification of the 

 disc and marginal bones posteriorly and anieriorly. The anterior rib is at- 

 tached to one marginal in advance of that to which it is connected in Chelone. 

 He called it Osteopygis, and exhibited a specimen of the type species — 0. 

 emarginatus Cope — of which about half the carapace and plastron were 

 preserved, and which indicated an animal of about the size of tlie green tur- 

 tle. It was presented to theAcademy by Dr. Samuel Ashhurst. 



Prof. Cope stated that he was more or less acquainted with four species of 

 the genus : 0. s o p i t u s (Chelone Leidy), 0. chelydrinus Cope, and 0. 

 repandus Cope, all of the same or larger size than the type. 



May 19th. 

 Mr. Vaux, Vice-President, in the Chair. 

 Twenty-nine members present. 



Prof. Cope called attention of the Academy to the rarity of Ophidian re- 

 mains, and to the fact that none had been discovered in North America up 

 to the present time. He then exhibited two vertebra; of a serpent of or near 

 the family of the Boas, from the green sand of Squankum, Monmouth Co., 

 N. J., which had been discovered by Dr. Knieskern. 



Peculiar interest attached to these specimens, from the fact that they 

 came from a bed which has recently been stated, by Conrad, to be an equiva- 

 lent of the older Eocene or London clay of the Thames valle3^ They con- 

 firm this identification exactly, since they belong to Owen's genus Pakeophis, 

 which is characteristic of those beds in England. They indicate a species 

 intermediate between the two larger described by Prof. Owen, and of some 

 fifteen feet in length. It was associated with remains of crocodiles, sting- 

 rays and saw-fishes, and was named, from its geographical and geological 

 location, Palaeophis littoraijs Cope. 



The type specimens belong to the Geological Survey of New Jersey, under 

 Prof. George Cook, and were lent by him for description. 



Dr. Hayden read a letter from Prof. Leo Lesquereux, identifying 

 the fossil plants of the coal formation of the south-west, as follows : 



" I was unwell when your boxes of fossil plants arrived, and was not able 

 to examine the specimens before now. 



1868.] 



