78 MR, T. GOODEY ON THE [Jan. 12, 
3. A further Note on the Gonadial Grooves of a Medusa, 
Aurelia aurita. By T. Goopry, B.Se., University Scholar, 
Zoological Laboratory, University of Birmingham.* 
[Received November 19, 1908. } 
(Plate XXLV.+) 
In a short paper read before this Society in February last + 
the occurrence of these grooves was noted and their structure 
and relations figured and described. The present paper is the 
outcome of observations which were suggested in the earlier 
communication and which prove that the grooves actually function 
as gonoduets. For the purpose, however, of making this paper 
complete in itself, it has been thought desirable to give a brief 
résumé of what the former paper dealt with. 
Tt was pointed out that the grooves are four narrow channels, 
best seen in a subumbrella aspect of the medusa, lying in the 
interradial axes. They have about the same diameter as the 
origins of the ordinary gastrov aseular canals, and are confined to 
the ventral walls or floors of the main passages from the central 
gastric cavity to the gastric pouches, and to the floors of the 
gastric pouches themselves. ‘They terminate in slightly funnel- 
shaped expansions at about the centre of each pouch. The 
boundaries of each groove are formed by two parallel ridges of 
epithelium which are raised up so as to form a channel between 
them. It was suggested that, functionally, the grooves serve as 
channels along which the sex-cells pass on their way to the 
exterior after having been shed into the gastric pouches at the 
time of spawning ; that they were, in short, incipient gonoducts 
eut off from the ‘general archenterie cavity or celenteron. 
It seemed desirable to ascertain whether these views were 
correct by the examination of specimens taken at the period of 
sexual maturity. 
In order to undertake this investigation I spent several weeks 
in the laboratory of the Marine Biological Station at Plymouth 
during the month of August, and there collected the necessary 
material. The specimens were all taken from the open sea and 
were of the type with very thick mesoglea; those worked on 
in the University laboratory for the first paper were estuarine 
specimens and were compar atively thin and discoidal. A large 
number of meduse, about two hundred in all, were examined with 
the view of finding sex-cells in the gonatlial grooves. Of these 
only a few, about tw elve, possessed grooves In which any obvious 
contents could be detected. Apparently the reason why | compara- 
tively few specimens exhibited grooves with eontents, was that 
* Communicated by Prof. T. W. Brrpes, Se.D., F.R.S., F.Z.S,. 
+ For explanation of the Plate see p. 81. 
* 'T. Goodey, P. Z.S. 1908, p. 55. 
