561 



SUMMARY OF CURRENT RESEARCHES 



BEIiATING TO 



ZOOLOGY AND BOTANY 



(PRIXCIPALLY INVERTEBRATA AND CRYPTOGAMIA), 



MICEOSCOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA. 



a. Embryolog-y.t 



Development of Stapedial Plate.J — Frank Pearce Reagan discusses 

 the origin of the plate-like cartilage which forms the distal portion of 

 the stapes. According to some, the entire stapes arises as a chondrifica- 

 tion in the second visceral arch. According to others, the stapes arises 

 from the otic capsule. According to a third view, the stapedial plate is 

 formed from the otic capsule, the rest of the stapes from the hyoid arch. 

 And there are other views. 



What Reagan has done is to remove from the young chick embryo 

 the auditory sensory epithelium, so as to test to what extent the stapes- 

 homologue, together with its stapedial plate, can develop in the absence 

 of a cartilaginous otic capsule, or in the absence of the stimulus to 

 which the latter owes its origin. 



Chick embryos of thirty-five to sixty hours formed the material. 

 One of the otocysts was completely or incompletely removed by insertion 

 into it of a very warm fine-pointed platinum needle, for a sufficient 

 length of time to coagulate the liquid contents of the otocyst, whereupon 

 the sensory epithelium would adhere to the needle when it was removed. 

 Another form of experiment was to transplant an otocyst. The eggs 

 were sealed after treatment and allowed to incubate for various lengths 

 of time. 



The results make it highly probable that the stapedial plate owes its 

 formation to the same general stimulus which initiates the cartilage- 



* 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. Tha object of 

 this part of the Journal is to present a summary of the papers as actually pub- 

 lished, and to describe and illustrate Instruments, Apparatus, etc., 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, Reproduction, and 

 allied subjects. 



X Journ. Exper. Zool., xxiii. (1917) pp. 85-108 (10 figs.). 



