780 SUMMAEY OF CUBRENT RESEARCHES RELATING TO 



SUMMARY 



OF CURRENT RESEARCHES RELATING TO 



ZOOLOaY AND BOTANY 



(jprincipally Invertehrata and Cryptogamia), 



MICROSCOPY, &c., 



INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.* 



ZOOLOGY. 



A. GENERAL, including Embryology and Histology 

 of the Vertebrata. 



Primitive History of the Vertebrate Body.f — In his seventh 

 essay Dr. A. Dohrn deals with the origin and differentiation of the 

 hyoid and mandibular apparatus of Selachians, and in the eighth with 

 the thyroids of Petromyzon, AmpMoxus, and the Tunicates. 



Dr. Dohrn criticizes very closely the speculations of a number of 

 recent observers, and expresses his own conviction that it is necessary 

 to bring morphological studies into the closest connection with phy- 

 siological and biological investigations ; it was for this purpose that 

 he built the Naples Aquarium, and he hopes to advance it by 

 adding a physiological laboratory. Morphology, in his view, has 

 become too one-sided, and too much restricted to one line of investiga- 

 tion. 



Formative Force of Organisms.^ — Dr. C. S. Minot thinks that 

 the conception that the forces of the ovum are so disposed that evolu- 

 tion of the adult organism is the mechanical result of the predeter- 

 mined interplay of those forces, is an inadequate explanation, and that 

 it must be supplemented, if not replaced, by another : " the formative 

 force is a generally diffused tendency, so that all parts inherently 

 tend to complete, by their own growth and modification, the whole 

 organism " ; evidence as to this may be arranged under three heads. 



1. Regeneration. This is a process which is co-extensive with life, 

 but varies greatly in different species ; from this it follows that each 

 individual has a scheme or plan of its organization to which it strives 

 to conform. " The act of regeneration of lost parts strikes the imagin- 

 ation almost as an intelligent pursuit by the tissues of an ideal pur- 



* 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, or 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 liave not been previously described in tliis country. 



t MT. Zool. Stat. Neapel, vi. (1885) pp. 1-92 (8 pis.). 



X Science, vi. (1885) pp. 4-6. 



