( 705 ) 

 SUMMAEY 



OF CTJKEENT EESEAECHES EELATING TO 



ZOOLOaY AND BOTANY 



(^principally Invertebrata and Cryptogamid), 



MIOEOSCOPY, &c., 



INCLUDING ORIGINAL COMMimiCATIONS FEOM FELLOWS AND' OTHERS.* 



ZOOLOGY. 

 A. VERTEBRATA :— Embryology, Histology, and General. 



a. Embryologry.t 



Formation of Polar Globules in Animal Ova.J— Prof. A. Weis- 

 mann and Mr. C. Iscliikawa have investigated the history of the polar 

 globules in various parthenogenetic ova. It will be remembered that, in 

 1885, the former of these writers discovered that a polar globule was 

 formed in the parthenogenetic egg of Polyphemus oculus ; the conversion 

 of the germinal vesicle into the globule, the cellular nature of the latter, 

 and its later division into two cells were observed, as well as the fate of 

 the portion of the nucleus which remained in the egg, and which became 

 the cleavage-nucleus. An account is now given of the fourteen cases 

 recently observed, chiefly by the authors of this paper, in which it is 

 certain that parthenogenetic ova give rise to one polar globule only ; 

 among these are Leptodora hyalina, Sida crystalUna, Cypris reptans, 

 Conochilus volvox, and an Aphis (Blochmann). 



A list is given of a number of cases in which two primary globules 

 have been observed, and this extends from Coelenterates to Mammals ; it 

 would have been much longer had it not been confined to a record of the 

 cases in which the describer distinctly states that the globules have been 

 successively given off from the nucleus of the egg. In a few cases where 

 sexual reproduction occurs, it has been stated that only one globule has 

 been observed ; but there is only one case, that of Gonothyreea Loveni, 

 in which the observer (in that case Bergh) remarks definitely that there 

 is never more than one globule. It is to be noted, however, that Bergh 

 himself states that the ova were difficult to isolate, and the finer processes 

 could only be seen with great difficulty through the walls of the 

 gcmozooid. 



If we confine ourselves to observations that may be certainly trusted, 



* 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 



X Ber. Naturf. Gesell. Freiburg i. B., iii. (1886) pp. 1-44 (4 pis.). 



