14 NATURAL SCIENCE. January, 



Dr. Blackmore figures specimens of Belemnitella lanceolata and B. 

 quadrata [we follow his nomenclature] , as evidence that the lower 

 margins of the aptychi fitted the upper margins of the belemnite- 

 guards ; but as to the imperfection of these specimens no one 

 acquainted with belemnite structure can have any doubt. Then 

 again, if it were possible to accept the homology of these aptychi with 

 the pro-ostracum, as advocated by Dr. Blackmore, it would be 

 impossible to regard their median line of junction as " probably a 

 contmuation of the ventral sulcus or the siphuncle " ; for whereas 

 these structures are ventral, the pro-ostracum, as the schoolboy knows, 

 is dorsal. In any case, the whole idea that the pro-ostracum of a 

 belemnite could become detached and form these twinned independent 

 calcified masses, is foreign to every conception of the cephalopod 

 shell, and would require substantiation by careful comparative 

 studies. 



Until some observer with Dr. Blackmore's care and enthusiasm 

 shall have discovered, in situ, specimens of these belemnites and their 

 supposed aptychi in juxtaposition, we do not think the suggestion 

 demands serious discussion. Not that we refuse to admit the 

 possibility of such a discovery ; only we should expect to find these 

 aptychi dorsal in position, not representing or replacing the pro- 

 ostracum, but lying within it at its anterior end. They would, in 

 fact, probably occupy the position of the nuchal cartilage in Sepia, a 

 structure which, as Von Ihering long ago pointed out, bears a 

 striking resemblance to an aptychus in form, and which, it may be 

 added, bears to the shell and soft parts much the same anatomical 

 relation as does the hood in a nautilus, or as the aptychus is presumed 

 to in an ammonite. Such a discovery would not strengthen the 

 case for the dibranchiate nature of the Ammonoidea ; nevertheless, it 

 would be of such interest that we hope Dr. Blackmore and others will 

 do their best to confirm the novel proposition now put forward by him. 



James Hall. 



Few persons with any pretensions to geological knowledge are 

 not familiar with the works of James Hall, for sixty years the State 

 Geologist of New York. At the recent meeting of the American 

 Association for the Advancement of Science, held at Buffalo, a 

 special celebration was inaugurated in his honour, and the veteran 

 geologist was present to receive the congratulations and acclamations 

 of his friends. The celebration was opened by Professor B. K. 

 Emerson, and Professsor Le Conte spoke on behalf of the Geological 

 Society of America. Professor Hall briefly replied. 



To give any sufficient account of the contributions to science by 

 this remarkable man, would be to fill a number of this journal. We 

 can therefore onl}^ briefiy refer to some of the chief labours to which his 

 long and active life has been devoted. In 1836 the official survey of 



