1884.] Mr Weldon, On the Head Kidney of Bdellostama. 107 



(2) On the Head Kidney of Bdellostoma. By W. Weldon, 

 B.A. 



The structure known as the "head kidney" was stated to con- 

 sist of a bunch of branched tubules, opening on the one hand into 

 the pericardium, and on the other into a central duct, which had 

 lost its primitive connection with the segmental duct. At its 

 posterior extremity blood was stated to enter the duct by means of 

 vessels passing from a glomerulus. 



The whole organ was compared to the suprarenal bodies of 

 higher vertebrates, and it was suggested that the evidence at 

 present obtained as to the embryonic development of the supra- 

 renals rather confirmed than disproved the view that they were 

 derived from parts of the primitive kidney. 



Functionally, an attempt was made to compare the suprarenals 

 of vertebrates with the glands always found, in one form or another, 

 in connection with the circulatory system of invertebrata. 



(3) On the early stages in the development of Balanoglossus 

 Aurantiacus. By W. Bateson, B.A. 



The author stated that through the great kindness of Dr W. K. 

 Brooks and the Council of Johns Hopkins University he had been 

 permitted to work during the past summer at the Chesapeake 

 Zoological Laboratory. He had thus been able to observe some 

 larval stages of Balanoglossus Aurantiacus (?sp.). The develop- 

 ment of this form from the egg was stated to be a direct one, no 

 form at all comparable to Tornaria being passed through. The 

 gastrula was anal, and the mesoblast arose as five archenteric diver- 

 ticula, while the central nervous system was described 'as being 

 formed by the delamination of an epiblastic plate in the median 

 dorsal line.' A brief comparison was made between the structure 

 of this larva and that of Tornaria and the Echinoderm larvas on 

 the one hand and with the early development of Amphioxus on 

 the other. 



