35 



March 15, 1854. 

 The President, in the Chair. 



Dr. A. A. Gould made some remarks upon the collection of 

 shells presented to the Society by the family of the late Col. 

 Perkins. Upon examining the collection, he found there 

 were many specimens of species not previously in the pos- 

 session of the Society, and many specimens superior to 

 those already in the cabinet. To one shell in particular, 

 he called especial attention, the large Argonaut, commonly 

 called Paper Nautilus, and which is the largest specimen 

 known to exist. Its measurements are 11| by 11 inches; 

 the next largest specimen, in the Museum of the College of 

 Surgeons, London, measures | of an inch less than this. 

 This large specimen was brought from the Indian Ocean. 



In the collection, is a series of Argonauts of different 

 ages ; some with and some without horns, but otherwise 

 similar in the number of undulations and tubercles. These 

 horns are often different on opposite sides of the shell, 

 and are often wanting on one side. Many of the shells 

 differ in symmetry in other respects, so as to render all 

 external appearances doubtful marks in the determination 

 of species belonging to this genus. 



The animal has been found to have no fixed connection 

 with the shell, and it has been a question if it were not a 

 parasite. It has, however, been recently determined that 

 the animal found in it truly belongs to the shell. It has the 

 power of sinking and rising in the water ; when crawhng 

 at the bottom or rising, the keel is uppermost ; and upon 

 reaching thesurface, the open portion of the shell becomes 

 uppermost. The animal employs a part of its arms for mo- 

 tive power, and with the remainder the shell is clasped. 



When the shell is broken, the animal has the pov*^er of 



