279 



Fig in 



Fig. 3. Sagittal section of intersiphonal region of a well developed bud of Botryllus 

 Gouldii (about 500 diameters). 



dorsal surface of the ganglion, extending a considerable distance 

 behind the ganglion. Posterior to the ganglion the tube enlarges be- 

 conoing thicker-walled. This larger portion of the tube bends at an 

 acute angle, returns toward the ganglion and fuses with it a little 

 dorsal to its posterior point and a little to the right of the mid line. 

 Before fusing with the ganglion the tube becomes soHd by the oblite- 

 ration of its lumen. Reference to the figures will give a clearer idea 

 of the structures than any verbal description could. 



The points of special interest are 1) the dorsal position of the 

 gland and its duct (similar relations are found in Molgula Manhat- 

 tensis, Cynthia partita and Boltenia Bolteni) ; 2) the complete absence 

 of any truly glandular portion; 3) the fusion of the posterior end of 

 the gland with the posterior end of the ganglion. 



In Julinia, recently described by Calman, we see the glandular 

 portion of the sub-neural organ very much reduced, only a few 

 vacuolated cells being present. These are fused with the posterior 

 end of the ganglion, giving in Julinia a condition much such as we 

 see in Botryllus, save that in the latter there are no functional gland 

 cells and the whole organ is dorsal and not ventral to the ganglion. 



The significance of these peculiar conditions can best be dis- 

 cussed after detailed comparison with many other species, upon which 

 I am now engaged. 



Marine Biological Laboratory Wood's HoU, Mass. 

 Aug. 6th 1895. 



