C 209 ) 

 SUMMAEY 



OF CUBEENT BESEAECHES EELATING TO 



ZOOLOOY AND BOTANY 



(principally Invertehrata and Cryptogamia), 



MICEOSCOPY, &c., 



INCLUDING ORIGINAL COMMUNICATIONS FEOM FELLOWS AND OTHERS.* 



ZOOLOGY. 



A. VERTEBR AT A r—Embryolo gy, Histology, and General. 



o. Embryology.t 



Germinal Layers-t — Dr. W. Wolff communicates a critical historical 

 review of the progress of knowledge from Pander onwards in regard to the 

 history of the germinal layers. He travels over somewhat familiar ground 

 in his account of gastrulation and the like, and gives expression to several 

 opinions which hardly seem to have been sufficiently focused. The prin- 

 cipal point in his article is his insistance that the mesoderm, or Mittelkeim 

 as he prefers to call it, cannot be said to arise from the endoderm. The 

 constituent cells have an independent pre-endodermic origin, and represent 

 the surplus of segmentation cells not used in forming the gastrula. It 

 might be argued that whatever be the sphere of a 'priori speculation, em- 

 bryological generalizations should be kept in as close touch as possible 

 with known facts. 



Karyoplasm and Inheritance.§ — Prof. A. Kolliker has some remarks 

 on the theory of Prof. Weismann with regard to the continuity of germ- 

 plasma. He urges that the idioplasm found in the nucleus of the fertilized 

 egg-cell increases in size during the course of development, but passes 

 with its internal structure unaltered into the nuclei of all the cells which 

 take part in the formation of the embryo ; and he denies, consequently, 

 the fundamental difference which is asserted to exist between somatic cells 

 and those of the tissues on the one hand, and the ovarian and seminal cells 

 on the other. He asserts that in the metamorphoses of the embryonic cells 

 into the specific elements of the tissues the primitive nuclear idioplasm 

 often completely retains its typical peculiarities, but in other cases retro- 

 gression takes place and this idioplasm disappears. 



Prof. Kolliker'g idea about the structure of idioplasm is this : we 

 cannot doubt that the basis for the whole organization of the future 



* The Society are not intended to be denoted by the editorial " we," and they do not 

 hold themselves responsible for the views of the authors of the papers noted, nor for 

 any claim to novelty or otherwise made by them. The object of this part of the Journal 

 is to present a summary of the papers as actually published, and to describe and illustrate 

 Instruments, Apparatus, &c., which are either new or have not been previously described 

 in this country. 



t This section includes not only papers relating to Embryology properly so called, 

 but also those dealing with Evolution, Development, and Reproduction, and allied 

 subjects. 



X Arch. f. Mikr. Anat.. xsviii. (1886) pp. 425-48 (1 pi.). 



§ Zcitbchr. f. Wids. ZooL, xliv. (1886) pp. 228-38. 



