19 



He stated at that time, (see Proceedings, Vol. IV, p. 396,) that 

 he had found a lenticular-shaped body connected with the eye, 

 and which might possibly be a lens. He had now satisfied him- 

 self that this body is truly a lens, and though not a perfectly 

 refracting organ composed of fibres, yet it is to be considered as 

 the rudimentary lens of the eye of this fish. 



Another point, more satisfactorily determined, is the presence 

 of a layer of cells beneath the choroid coat, resembling the retina, 

 and corresponding to it in position. 



A sclerotic coat, a choroid coat, a layer resembling the retina, 

 a lens, and a nerve, have now been found in the eye of the 

 Amblyopsis. Nevertheless, it is an imperfect eye, and the areo- 

 lar tissue and skin which cover it prevent all transmission of 

 light to it, except in a different condition. It has heretofore been 

 compared with the eyes of the invertebrate animals, but the 

 above observations show that it is more like the eyes of other 

 vertebrates. 



The organ of hearing was examined by Dr. Wyman, in a dif- 

 ferent manner, and the semicircular canals were seen to be 

 largely developed, and the vestibules to contain large otolithes. 



The President exhibited one of a series of specimens of 

 Ornithichnites obtained by exchange w^ith Pres. Hitchcock, 

 and numbering from fifteen to twenty different species. 

 This specimen was prepared in a peculiar way, a section 

 having been made directly through the fossil so as to 

 show the impression from four points of view. It was the 

 track of the Ornithopus gracilis. 



Mr. Sheafe presented a specimen from Dr. Codinse, of 

 Philadelphia, found near Memphis, Tennessee. It resem- 

 bled somewhat an extremity of a large fossil bone, with a 

 central cavity. 



Dr. Wyman, from a cursory examination, remarked that 

 it probably was not a bone, but one of those clay masses 

 commonly called clay-stone. The specimen could be split in 

 layers at the extremity as well as on the shaft, which is not 

 a character of fossil bone. Its form was imitative of bone, 

 but clay-stones take on great varieties of form. Many sub- 



