Richard Owen, Esq., on Comparative Osteology, 329 



13. This theory of double movement completely solves all 

 the mysteries attendant on the formation of coral reefs, — 

 the gradual descent permitted beds of coral of very great 

 thickness to be formed, the ascent brought the whole again 

 to the surface, or above it. 



Synopsis of the Hunterian Lectures on Comparative Osteology. By 

 EiCHARD Owen, F.R.S., Hunterian Professor to the College.* 



Lecture i. — Introductory. — The aims of Osteology illustrated 

 by the comparative anatomy of the Temporal Bone. 



Lecture ii. — Development of the vertebral column. — Notochord. 

 Neural arch. Centrum. Arrested stages in Cartilaginous Fishes. 

 Metamorphosis of vertebral column in Batrachia. Final purpose of 

 the observed gradations of structure. 



Lecture hi. — Development of the Skull. — Its stages exemplified, 

 with special superadditions, in the Ammocete, Lamprey, Rays, 

 Sharks, and Lepidosiren. 



Lecture iv. — Persistent notochord in Lepidosiren and the earliest 

 extinct Fishes. Forms of the centrum in ordinary osseous Fishes. 

 Characters and divisions of the vertebrae of the trunk. Ribs and 

 costal appendages. Modes of formation of the haemal canal in the 

 tail. Numbers of vertebrae in different fishes. Peculiar modifica- 

 tions of vertebrae at the two extremities of the trunk. No sternal 

 ribs or sternum. Analogues of the sternum from the splanchno- 

 skeleton and exo-skeleton. Combination of exo- with endo-skeleton 

 in the vertical fins of Fishes. Modifications of the fin-ray charac- 

 terising the Acanthopterygian and Malacopterygian orders of Cuvier. 

 Modifications of the caudal fin characterising the Homocercal and 

 Heterocercal fishes of Agassiz : prevalence of Heterocercals in the 

 older secondary strata. Ichthyodorulites. Spine of Balistes. Adapta- 

 tion of the unfettered vertically extended caudal vertebrae of fishes 

 to their habits and place in Nature. 



Lecture v. — ^Bones of the head in osseous fishes : large propor- 

 tional size of skull, its general characters, and firm connection with 

 trunk. Squamous sutures of most of the bones. Principal promi- 

 nences and cavities of the skull. Classification of the bones of the 

 head. Determination of the bones according to their special and 



* We are fortunate in having an opportunity to lay before our readers 

 the above important Synopsis, containing the present views of the highest 

 authority on Comparative Osteology. The Lectures are now delivering in 

 the Theatre of the Royal College of Surgeons of England by the illustrious 

 Professor. 



