THE INFLUENCE OF SALT AND OTHER SOLUTIONS ON THE FROG. 181 
that is there going on as a result of the bilateral closure of the blasto- 
ore. 
F é. 1:33 per cent.—The tail is rather longer and the fin broader than 
before. The yolk-plugis wholly withdrawn. A lens is formed and nerve- 
fibres are differentiated. 
Three notochords—ordinary, ‘neural’ and ‘enteric’ 
the last. 
«. 1:17 per cent.—In this solution development is nearly normal. 
There are three pronephric funnels and the peritoneal cavity is large. An 
‘enteric’ but not a ‘neural’ notochord is found. 
are found, as in 
It may be pointed out that the distorted developments produced by 
these concentrated solutions of sodium sulphate and urea are not like the 
effects of, for example, dextrose. 
The reasons for believing that the tissues are permeable to these two 
substances have been given, and it does not seem likely that the increased 
osmotic pressure plays, at any rate, an important part in the process. 
At the same time, it must be confessed that these experiments do not, 
of themselves, conclusively prove that the embryo absorbs no water during 
the closure of the blastopore. It would be advisable to institute a series 
of ‘desiccation’ experiments, and also to grow the embryo in stronger 
solutions of dextrose. This it is hoped will be done next season. 
Apart, however, from this particular problem, the experiments above 
described have brought out several points which throw an interesting 
side-light on certain of the processes of normal development : for example, 
the reduction of the lumen and increase in thickness of the walls of the 
medullary tube in those cases in which the embryo remains spherical 
recalls the ‘ solid’ medullary groove of Petromyzon, Teleostei, and certain 
other fishes ; again, the way in which the medullary groove closes in 
certain cases resembles the mode of its closure in Amphioxus ; the forma- 
tion of the notochord in many of these solutions from the whole thickness 
of the archenteric roof is just what occurs normally in some Anura, the 
Urodela, and Petromyzon. These instances will suffice to show that ex- 
periments of this kind may be fruitful in results which can be applied to 
the causal explanation of developmental events. This and kindred work 
will, it is hoped, be continued, and for all these reasons the Committee ask 
that they may be reappointed, with a renewal of the grant. 
Occupation of a Table at the Zoological Station at Naples.—Report of 
the Committee, consisting of Professor 8. J. Hickson (Chairman), 
Rey. T. R. R. Stessine (Secretary), Professor E. Ray LANKESTER, 
Professor W. F. R. Wetpon, Professor G. B. Howes, Mr. A. 
SEDGWwick, Professor W. C. McIntosn, and Mr. G. P. BippEr. 
Tue table has been occupied during the greater part of the year by 
Mr. Geoffrey Smith, B.A., who has been engaged in a research upon the 
Rhizocephala. 
Dr. Edith M. Pratt visited the station in April and, by the kindness 
of Dr. Dohrn, was allowed to occupy a table during her stay there, the 
Association’s table being then in the occupation of Mr. Smith. 
The Committee have to lament the decease of their esteemed colleague 
