390 TH. H. MONTGOMERY jr., 



5. Cells of the Proctodaeum and Stomodaeiim. 



The epithelium of these two portions of the intestine is known 

 from embryological evidence to be an iuvaginated portion of the hypo- 

 dermis, and this is corroborated by the histological evidence. In 

 the mouth and anal regions the undiiferentiated hypoderraal cells pass 

 by gradual transition into the modified cells of the larval oesophagus 

 and rectum. In each of these large modified cells (Fig. 9) we find a 

 proportionately large nucleus, with deeply staining chromatin, and 

 with a large chromatin nucleolus (Fig. 8 n.2). The genesis of the 

 latter is the same as that already described for the cells of the feet. 



The form of the cells is illustrated in Fig. 8. A cuticle (Cut) 

 is present on only one surface of the cell (that toward the intestine) ; 

 it is of great diameter and transversed by numerous fine, radial 

 pores, which appear to extend for some distance into the cell body. 

 The cuticular structure would show the cell to be essentially assimi- 

 lative in function. 



These brief observations were made in the spring of 1898, but 

 I have deferred sending them to press until now, with the hope of 

 making a more extended study. Work on other lines, however, has 

 prevented me from giving the necessary time, and hence these few 

 facts are given with the view of calling attention again to the chro- 

 matin nucleolus. 



University of Pennsylvania, 

 Philadelphia, U. S. A., 24. July 1899. 



