PROCEEUINGS or SOCIBTIKS. '617 



The primary plates, secondary pktes, and tlie proximal portion 

 of the flabellilbrm processes are stated to constitute the body of 

 the tooth — the distal extremities of tlie fiabelliform processes the 

 skirfinr/s of the enteric region of the body of the tooth ; the keel 

 fibres wholly form the keel ; while the short enamel rods compof^e 

 the thin white layer on the dorsal surfa.r? of the tooth — the 

 enamel. 



The histology of the tooth is remarkable as exhibiting apparent 

 inconsistencies in dilierent lines of section. A \ertical section of 

 the tooth presents the appearance of vertebrate bone, lacuna', 

 canalicidi, and lamellae ; while a transverse section displays some 

 regions resembling dentine (the body of the tooth), and others 

 having the closest similitude to an oblique section of the shell of 

 some ^lollusca, such as Pinna. 



The author then proceeds to describe in detail and with par- 

 ticularity the form and progressive growth of the several elements 

 of the tooth, as they are met with in examining the growing 

 extremity, and proceeding from it towards the mature structure, 

 as long as the elements are susceptible of isolation and individual 

 examination. The anatomy of the soldering particles, and their 

 relation to the ])roduction of the cavitary structure of the tooth, 

 is specially dwelt upon. The soldering particles are supposed to 

 be isolated at first, but as they enlarge they become connected by 

 a thin film from their upper and uuder faces. This occurs before 

 the final consolidation of the tissue, and befoi-e the soldering 

 particles are indissolubly connected with, and tliemsehcs in- 

 dissolubly connect, the contiguous elements of the tooth. At 

 this stage these pai-tieles are still susceptible of isolation, and they 

 may be separated en masse, being held in relative position by tlie 

 films that connect them. The soldering particles and the con- 

 necting films thus constitute a tubular system, which has an 

 independent existence before the final consolidation of the tissue, 

 and this tubular system is introduced between, and interpolated 

 among, the previously existing elementary parts of the tooth. 



The author concludes by expressing a coincidence of opinion 

 with Dr. Carpenter, that the minute structure of the tooth is 

 essentially of the same nature as that of the shell of the Echinida' 

 generally. 



Hull Micro-Philosophical Society. 



The annual meeting of this Society was held in the committee- 

 room of the Hull Literary and Philosophical Societj^, on the 

 6th September, preliminary to the foin-th sessional course of 

 microscopical exhibitions and discussions, when George Norman, 

 Esq., was re-elected President, and the other officers were appointed. 

 The number of members is already twenty-two, being at present 

 limited to twenty-five. The Society progresses steadih' in the 



