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describe and figure these. I do not understand, however, the 

 impression which ' consists of an excavation of about fifteen 

 inches long, and of an inch wide, dividing into two branches.' 

 If there be two branches, they could not have been made by one 

 unio. It is not at all unlikely that two individuals may have 

 been travelling together. 



" Many of these linear marks and grooves are very obscure, 

 and I am much inclined to believe that many of them, which are 

 regarded as sun-dried cracks, are really of vegetable origin. 

 Some of the AlgcB anastomose, and I do not see why some of 

 these obscure impressions, may not be attributed to that form of 

 imperfect vegetation. Other algae have their branches inoscu- 

 lating, and of course, if impressed on a plastic surface, they 

 would present the form of sun-dried cracks. We are daily 

 getting more and more evidence of the cogeneric vegetation 

 existing in the same horizon whh the footmarks of the so-called 

 New Red Sandstone of Connecticut, Pennsylvania, &c." 



The President exhibited a cast of Pterodactyl longiros- 

 tris, a fossil flying reptile, and pointed out its peculiarities. 



The head was very large compared with the body, and the 

 lower jaw very long, whence its specific name. The head and 

 teeth preclude the idea of its belonging to the same class with 

 the bat, an animal which it might somewhat have resembled 

 when flying. Its sternum is oblong as in the Saurians, and does 

 not resemble the sternum of birds. The principal peculiarity is 

 the fold of the skin extending from the tip of the finger along 

 the body, enabling the animal to fly, as has been supposed. 



Prof Jeffries Wyman remarked that there had always been 

 some degree of doubt whether the pterodactyl had the power 

 of flying, as until recently the sternum had always been 

 found to be a flattened shield without a projecting keel. Herman 

 Von Meyer has quite lately, however, detected a sternum with a 

 broad keel, like that of birds, to which powerful muscles might 

 have been attached, thus rendering flight easy. 



Dr. Silas Durkee exhibited a portion of a Guinea Worm, 



