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SUMMARY OF CURRENT RESEARCHES RELATING TO 
SUMMARY 
OF CURRENT RESEARCHES RELATING TO 
ZOOLOGY AND BOTANY 
( principally Invertebrata and Cryptogamia\ 
MICROSCOPY, Ac., 
INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS* * * § 
ZOOLOGY. 
A. VERTEBRATA : — Embryology, Histology, and General. 
a. Embryology, t 
Human Embryo twenty-six days old. f — Mr. F. Mall gives an 
account of a very young human embryo so well preserved and so perfect 
in all respects as to justify careful study. The memoir consists entirely 
of descriptive details, some of which, however, may be noted. The 
embryo was flexed upon itself so as almost to form a circle ; the nasal 
pit was a large shallow depression, well exposed on both sides. Three 
branchial arches were visible on the right, and four on the left side. 
There were twenty-seven right and twenty-four left protovertebrae. 
The extremities were well marked, and the anterior were somewhat 
larger than the posterior. The neural tube, when straightened, measured 
from end to end 17 mm. There was no indication of a permanent optic 
nerve ; the vagus was composed of two enormous ganglia. Though there 
were no sympathetic ganglia, there were marked branches extending from 
the first six dorsal nerves. The hulk of the framework of the skeleton 
was composed of multipolar cells. The Wolffian body was very large 
and somewhat lobulated ; the ducts extended throughout the body. The 
cloaca was pyramidal. 
Origin of Nerve-cells and Fibres in the Embryo. §— Prof. M. v. 
Lenhossek, using Golgi’s method, has studied the origin of the nerve- 
cells and fibres in embryonic chicks and ducks. The first differentiation 
of the medulla is the establishment of a primary supporting system of 
* 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. t Journ. Morphoh, v. (1891) pp. 459-80 (2 pis.). 
§ Verb. Naturf. Gesellsch. Basel, ix. (1891) pp. 379-92 (2 figs.). 
