SUMMARY OF CURRENT RESEARCHES 
RELATING TO 
ZOOLOGY AND BOTANY 
(principally invertebrata and cryptogamia), 
MICROSCOPY, Etc.* * * § 
ZOOLOGY. 
VERTEBRATA. 
a. Embryolog-y.f 
Development of Olfactory Nerve.J — Prof. W. A. Locy finds that in 
Acanthias two elements are joined in the olfactory nerve, — the dorsal 
median nerve, hitherto unrecognised, and the laterally placed main 
olfactory. The lateral bundles, though differentiated a little later than 
the mesial element, outstrip it and become the main olfactory. Both 
groups of fibres arise long before the lobe is developed. 
The elongated slender connective between brain and bulb, which in 
the adult condition simulates a nerve, is a secondary formation gradually 
produced by modification of the lobe. The true nerve is the group of 
relatively short fila olfactoria terminating in the glomeruli of the bulb. 
It is necessary to distinguish clearly between this true nerve and 
the tractus. “ However close the superficial resemblance may be, there 
can be no homology between a hollow tractus derived from the lobe and 
a structure of similar appearance composed of fila olfactoria.” 
As far as is known a tractus is always developed in Selachii. Jn 
Protopterus and Amphibia there is none. In Hatteria and Lacerta a 
tractus is present ; in Anguis, Amphishsena , aud Typhlops there is none ; 
nor is there any in Amia. In Teleosts both conditions are found ; thus 
there is a tractus in Cyprinus but none in Lophius. 
The “ accessory olfactory ” described in this paper seems to have 
been noticed before, but never attended to. Till more is known about 
it, the less said in regard to its possible homology the better. 
Development of Frog’s Head.§ — Herr H. K. Corning, in studying 
this, has directed his attention particularly to the sense-organs, nerves, 
* 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 ix-en 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. J Anat. Anzeig., xvi. (1899) pp. 273-90 (14 figs.). 
§ Morphol. Jahrb., xxvii. (1899) pp. 173-241 (2 pis.). 
