55 , 



I am unable to say whether the species is identical with either of 

 the others or not. 



Mr. John Green read a paper entitled — 



SOME OBSERVATIONS ON THE STRUCTURK OF BONE IN 

 FYTIION. 



The ribs of Python are hollow, without cancelli, except at the 

 vertebral extrenaity, and in thickness they are about one fifth or 

 one sixth of the diameter of the bone. In the macerated and 

 dried bone, the cavity contains only adipocire and some remains 

 of a lining membrane. The nutritious artery enters near the 

 vertebral end of the rib, and passes directly through into the 

 medullary cavity. 



The vertebra; are made up of a very dense osseous tissue, 

 with' cancelli in the upper and posterior parts of the bodies, and 

 in the interior of the spinous processes, and to a small extent in 

 the arches on each side of the great foramen. 



The microscopic structure of the ribs is remarkable in the 

 total absence of Haversian canals. The lacuna; and canaliculi 

 are distinct, and the lamellar structure well marked. The 

 laraellffi are arranged in two series, the first (fundamental lamellae 

 of Kolliker) parallel to the external surface of the rib, and the 

 second series concentric with the medullary cavity and cutting 

 off many of the first series at an acute angle. This internal 

 series of lamella; appears to be a secondary deposit, taking place 

 after the formation (by absorption) of the central cavity, and is 

 homologous with the lamella; of the Haversian canals in human 

 bones, the medullary cavity itself corresponding to the Haversian 

 canal. 



Under the microscope, the vertebra; present lamellie for the 

 most part parallel with the exterior of the bone, with lacunae 

 and canaliculi well marked, but with a few canals which in the 

 bodies have an antero-posterior direction, and pass directly 

 through the thickness of the bone. These canals vary consid- 

 erably in size, do not branch or anastomose, and are generally 

 not surrounded by lamellae, although, in a few canals, one or two 

 lamellae have been observed. The lacunjE correspond in arrange- 

 ment with the lamellar structure of the bone, and are entirely 

 independent of the canals. 



