Bicknell.] 



58 [November 16, 



Mr. Bicknell remarked that he had found great numbers of 

 Isthmia nervosa on the fronds of a species of Callitham- 

 nion, off Portland harbor, yet the mud dredged from the 

 same place contained none of their frustules ; he could aej 

 count for their total disappearance only by supposing them to 

 have been absorbed by the water. 



Prof. A. Hyatt referred to some points in the embryology 

 of the fossil Nautiloids, discovered by a microscopic examina- 

 tion of the umbilici of some fossil specimens. He showed 

 that the embryos of the same age are quite variable in their 

 mode of development. 



Mr. A. Tuttle described a form of JParamcecium, from 

 Fresh Pond, Cambridge, differing from the common species 

 in having a much smaller vestibule, occupying only one-fifth 

 of the length and one-eighth of the breadth of the animal. 



Mr. Bicknell described the structure of whalebone. He 

 said the lamellae were composed of a single row of hairs set 

 closely together and united into a plate at thfe base by a 

 horny sheathing, while their ends were free. These hairs are 

 hollow throughout their entire length, and he thought each 

 one probably contained a nerve-fibre. 



Wednesday, November 16, 1870. 



The President in the Chair. Fifty persons present. 



Count Pourtales made some remarks on the constitution 

 of the bottom of the ocean off the east coast of the United 

 States, south of Cape Hatteras, as developed by the sounds 

 ings and dredgings of the U, S. Coast Survey, 



