972 NOTES ON A BBROID OF PORT JACKSON, 



the stomach. These ramifications become finer and finer and end 

 as fine capillaries outside the surface of the stomach. Towards 

 the mouth the network is very fine and indistinct, but can be 

 demonstrated by means of injection with osmic acid without 

 difliculty. 



The vascular reticulation of the flaps consists of nearly parallel 

 longitudinal canals, which run upwards and end vertical to the 

 surface, diverging accordingly in graceful curves. These stems 

 are connected with one another by transverse canals of similar 

 width so that a ladder-shaped network is formed which resembles 

 the skeleton of Spongelia in shape. 



In the middle between each pair of meridian canals, the vessels 

 of the reticulation are much larger than near the stem, their 

 diameter is here almost three times as great. 



The Sexual Froducts. 



Ripe sexual products are exclusively found in those parts of the 

 vascular reticulation which are most remote from the meridian 

 canals. The latter never contain ripe ova or spermatozoa. 



In this aspect also, Neis difiers essentially from Beroe (3, p. 62) 

 and Idyia (1, p. 285), as in these it is just the meridian canals and 

 the proximal part of the vascular reticulation which contain the 

 sexual products, whilst the more distant parts of the vascular net 

 work remain sterile. I have made no observation which would 

 tend to prove an Ectodermal origin of the sexual product, which 

 Claus (4, p. 299), and Richard Hertwig (6, p. 426) assume. 



As compared with Beroe, Neis accordingly shows a greater 

 differentiation ; the maturing area of the sexual cells is conveyed 

 from the meridian canals to the reticulation. 



According to Chun (.3, p. 191), the female sexual products are 

 modified Epithel cells. I assent to this assumption, but I believe 

 that the ora are Sub-epithelial and do not lie on the surface. In 

 a transverse section through the meridian canal it can easily be 

 observed, that cells lie beneath the Eutodermal Epithelium as 

 highly coloured (Alumn Carmin) nuclei lie in abundance between 

 the canal Epithelium and the Gallert. Such nuclei are also found 



