20 HENRY B. BRADY. 



since in their ancestors the anterior pore of the head-kidney 

 appears to have become specialised as the permanent opening 

 of the Miillerian duct. 



With reference to the posterior position of the head-kidney in 

 Aves we have only to remark, that a change in position of the 

 head-kidney might easily take place after it acquired an inde- 

 pendent development. The fact that it is slightly behind the 

 glomerulus would seem to indicate, on the one hand, that it has 

 already ceased to be of any functional importance ; and, on the 

 other, that the shifting has been due to its having a connection 

 with the Miillerian duct. 



We have made a few observations on the development of the 

 Miillerian duct in Lacerta muralis, which have unfortunately 

 led us to no decided conclusions. In a fairly young stage in the 

 development of the Miillerian duct (the youngest we have met 

 with), no trace of a head-kidney could be observed, but the cha- 

 racter of the abdominal opening of the Miillerian duct was very 

 similar to that figured by Braun.^ As to the backward growth 

 of the Miillerian duct, we can only state that the solid point of 

 the duct in the young stages is in contact with the wall of the 

 Wolffian duct, and the relation between the two is rather like 

 that figured by Fiirbinger (PI. I, figs. 14-15) in Amphibia. 



Notes ow some of the Reticularian E-hizopoda of the 

 " Challeisiger" Expedition. By Henry B. Brady, 

 F.R.S. With Plates III, IV, V. 



I. — Oil new or little known Arenaceous types. 



The quantity of material, obtained by dredge and tow-net, 

 brought home by the scientific staff of the " Challenger" 

 Expedition is so vast, and the conditions under which it was 

 collected are so varied, that much time must elapse before any 

 detailed account of the results of its examination can be made 

 public. So far as the microzoa are concerned the mere wash- 

 ing, sorting, and examining under the microscope of so large a 

 number of samples of the sea-bottom, to say nothing of the 

 surface-gatherings, has been a long and tedious process ; but 

 the time required for their complete investigation and for the 

 preparation of the plates necessary for the illustration of each 

 group of organisms is likely to be an even more considerable 

 source of delay. To no section of the work does this apply 



' Loc. cit. 



