Royal Society. 81 



Our space will not permit us to indulge in further quotations 

 from this interesting portion of the volume ; but our readers can form 

 some idea of the research and labour that have been employed when 

 we say that no less than ten species of the order Cetacea have been 

 added to the British list ; and although the illustration of Zipluus 

 cavirostrits at page 428 exhibits an impossible tail (being vertical 

 instead of horizontal) , yet the woodcuts and vignettes throughout 

 the volume are really beautiful as works of art, while the literary 

 and scientific portion is well worthy of the distinguished naturalist 

 to whom, principally, we are indebted for this valuable contribution 

 to the zoology of the British Islands. 



PROCEEDINGS OE LEARNED SOCIETIES. 

 ROYAL SOCIETY. 



March 12, 1874. — Joseph Dalton Hooker, C.B., President, in the 



Chair. 



" Contributions to the Developmental History of the Mollusca. 

 Sections I., II., III., IV." By E. Rax Lankester, M.A., Fellow 

 of Exeter College, Oxford. . 



Section I. The ovarian Egg and early development of Loligo. 



The points of greatest interest to which the author draws 

 attention in the present memoir are : — 



1. The explanation of the basketwork structure of the surface 

 of the ovarian egg by the plication of the inner egg-capsule. 



2. The increase of the yelk by- the inception of cells proliferated 

 from the inner egg-capsule. 



3. The homogeneous condition of the egg at fertilization. 



4. The limitation of yelk-cleavage to the cleavage-patch. 



5. The occurrence of independently formed corpuscles (the 

 autoplasts) which take part in the formation of the blastoderm. 



6. The primitive eye-chamber, formed by the rising up of an 

 oval wall and its growing together so as to form a roof to the 

 chamber. 



7. The origin of the otocysts by invagination. 



8. The rhythmic contractility of a part of the wall of the yelk- 

 sac. 



9. The disappearance of the primitive mouth, and the develop- 

 ment of a secondary mouth. 



10. The development of a pair of large nerve-ganglia by in- 

 vagination of the epiblast immediately below the primitive eye- 

 chambers. 



Ann. & Mag. N. Hist. Ser. 4. Vol. xiv. 6 



