Royal Society. 323 



vision — "tliG first-bora lands of our mother-earth joyously basking 

 in the smiles of the sun, bathed in the tear-drops of the clouds, and 

 scarred with the blasts of the waves and the storms." His compo- 

 sition is founded on the well-based theories of the ' Principles' and 

 * Siluria ;' and the judiciously chosen colours on his canvas have 

 been supplied by the proved researches of modern geologists. 



The author's style is florid, but often good ; and, though objections 

 may be made to occasional loose or obscure passages, to the too 

 widely printed pages, and to the pompous classification of the wood- 

 cuts as "plates" and " liguographs," yet we recommend this little 

 book as well worth the attention of geologists, students, and others : 

 it has numerous woodcut illustrations, some of theni of superior 

 execution. 



PROCEEDINGS OF LEARNED SOCIETIES. 



ROYAL SOCIETY. 



December 22, 1859. — Sir Benjamin C. Brodic, Bart., President, in 



the Chair. 



"On the Structure of the Chorda dorsalis of the Plagiostomes 

 and some other Fishes, and on the relation of its proper Sheath to 

 the Development of the VertebrEe." By Professor Albert Kolliker, 

 of Wiirzburg. 



I take the liberty to present to the Royal Society the results of an 

 extended series of investigations into the development of the vertebrae 

 of the plagiostomous and some other fishes. 



I. Chorda dorsalis. 

 A. Sti'ucture. 



The chorda dorsalis of the Plagiostomes, of Chimcera, Acipenser, 

 Scaphirhynchvs, Toxodon, and Lepidosiren, sho\y% four distinct parts, 

 viz. — 



1st. The outer elastic raemhrane, a homogeneous clastic coat, 

 which is not unfrequently perforated with holes of different sizes, of 

 the same kind as those of the fenestrated membrane of Ilenle. 



2nd. The proper sheath, formed of connective tissue of fibrous 

 appearance, and generally provided with many plasm-cells. 



3rd. The inner elastic layer, a reticulated clastic membrane ; and 



4th. The (jelaiinous substance of the chorda itself, made up of 

 soft cartilage-cells, of different sizes and generally provided with 

 nuclei. 



Of these four Ia3'er3 it would seem that only the third and fourth 

 are present in the higher animals, from the Amphibia (with the ex- 

 ception of the B.T'rachians) upwards; if, at least, my oj»inion be 

 correct, that the structureless envelope of the chorda of these animals, 

 generally called the sheath })roper, corresponds to the third layer in 

 the cartilaginous fishes. On the other hand, it seems that many of 



