THE ANATOMY AND DEVELOPMENT OF PERIPATCS NOVaE-BRITANNIAE. 



between the basal membrane and the cuticular membrane are stretched irregular 

 strands of protoplasm up the centre of which mar often be traced a fine supporting 

 axis which perhaps represents a cell-membrane. The strands of protoplasm are beset 

 with innumerable eosinophile globules of varying sizes. The supporting axes mentioned 



Fig. -5. Posnox of the exdodkbx of P. novae-britantiiae ax stage x. 

 The coarsely granular endoierm-cells or trophocytes lie upon the manbana propria projecting freely into 

 the trophic cavity. The cells are often separated by wide intervals. 



above, which stretch from membrane to membrane, obviously serve the purpose of 

 holding the granules in position and, on the other hand, the cuticular membrane 

 which is a temporary structure and not always if ever present in the adult, serves 

 the purpose of providing a point cf appui for the strands of protoplasm with their 

 globules. The nuclei lie near the base of this thickened epithelium. 



Fig. 6. Pobtiox of the wall of the smxn of P. norat-Vritattni<u ax stage xl. 

 The endoderm has become a thickened compact layer containing n ume r ou s eosinophile c*"%"tfl« The 

 cuticle at the inner surface of the endoderm has become (artificially) separated at this point from the eeDs 

 which secreted it. this portion of the section having been selected for representation in order show the 

 membrane as a distinct cuticular product. The protoplasmic matrix of the globules is not shown in die figure. 



In Stage XII this remarkable epithelium ^which has meanwhile still further in- 

 creased in thickness) with its contained eosinophile globules is, in my preparations, 

 in process of undergoing complete disintegration. The cuticle is ruptured locally and 

 the globules are passing singly and en masse into the gastral cavity presumably 

 preparatory to their resorption. In other words, the wall of the gastral cavity is 

 undergoing a histolytic change and the scene presented while it is doing this, is one 

 of the utmost disorder 1 . In this stage the globules average larger and are somewhat 

 less numerous than in the preceding stage. 



These globules are clearly the product of the metabolism of the endoderm cells 

 which have converted the nutrient matter derived from the maternal fluids into 



1 Tbis is true of the posterior region of the particular embryo referred to. In the anterior region the 

 changes are far less advanced although there are indications of their approach. 



4—2 



