1893.] NATURAL SCIENCES OF PHILADELPHIA. 1 1 



" On a now extinct species of Cyprinidse," by Edw. D. Cope. 



"On the Inheritance of Modifications due to the Disturbance of 

 the Early Stage of Development in the Japanese Domesticated 

 Races of Gold Carp," by John A. Ryder. 



" The Vascular Respiratory Mechanism of the Vertical Fins in the 

 Viviparous Embiotocida?," by John A. Ryder. 



January 17. 

 The President, General Isaac J. "Wistar, in the chair. 

 Fifty-three persons present. 



Papers under the following titles were presented for publication : — 



" Catalogue of the Crustaceans in the Museum of the Academy 

 of Natural Sciences of Philadelphia," by Benjamin Sharp, M. D. 



" Description of a New Species of Neotoma," by Witmer Stone. 



Mr. Chas. P. Perot was elected Treasurer to fill the vacancy 

 caused by the death of Mr. Isaac C. Martindale. 



January 24. 

 The President, General Isaac J. Wistar, in the chair. 

 Fifty-nine persons present. 



A paper entitled " New Species of North American Fungi from 

 various localities," by J. B. Ellis and B. M. Everhart, was presented 

 for publication. 



The deaths of Dr. J. S. Newberry and Sir Richard Owen, corres- 

 pondents, were announced. 



The Forms of Edentulous Jaws in the Human Subject. — Dr. Har- 

 rison Allen demonstrated the peculiarities of the edentulous 

 upper and lower jaws of the human subject. He held that the 

 statement made that the jaws exhibit the result of uniform absorp- 

 tion of the alveolar nrocesses was not true. The bone tissue which 

 held the teeth in place being a complemental structure is indeed 

 rapidly absorbed after the teeth are lost. But when the alveolar 

 processes have disappeared, a secondary process of adaptive hyperos- 

 tosis takes place. These statements relate in the main to the upper 

 jaw, but the conclusions can be applied also to the lower jaw. 



This adaptive process occurs in three regions, namely, that for 

 the incisor teeth, that for the canine tooth and the first bicuspid tooth, 

 and that for the second bicuspid tooth and the molar teeth. These 



