PEROPHORA ANNECTENS. 67 



of the wall, as it is seen in section (tig. 22 st' ., pi. iii), 

 givinor a striated appearance to the sections. These cells 

 bsar short cilia, and on the inner surface of the entire 

 epithelium is found a series of very regular elongated 

 granules deeply stained by haematoxylin (fig. 22 c. g.) 

 Whether or not these granules are produced by an artifi- 

 cial breaking to pieces of a cuticular lining of the epithe- 

 lium I am unable to say positively. However, from their 

 constancy and regularity, and from the fact that in some 

 refjions their fjreatest leno-th is directed at rijjht ancrles to 

 the surface of the epithelium, I believe the intervals be- 

 tween the blocks are the expression of fine pores which 

 penetrate a cuticula. I have not been able to decide 

 whether the cilia are situated within or between the pores. 

 This porous cuticula, if such it be, extends through the 

 entire length of this portion of the intestine, even into 

 the mouth of the cceca at the junction of these with the 

 chylific vesicle. It does not, however, extend into the 

 extreme depths of the coeca (fig. 26, pi. iii).^"' 



Two kinds of cells enter into the structure of the walls 

 of the coeca themselves. The proximal portions, and a 

 greater part of their extent are composed of cells quite 

 similar to those found in the walls of the duodenum. 

 Their nuclei are, however, more distinct here than there 

 (figs. 24, 25 and 26, pi. iii). At the extreme tips of the 

 coeca are found a comparatively small number of cells con- 

 siderably larger than those of the other portions. The 

 boundaries of these are also more clearly defined, as are 



* It is possible that these structures ane similar to the enlarged portions 

 of the "cordons protoplasmiques " described by Maurice ("88, p. 168) as 

 existing in the epithelium of the oesophagus and rectum of Fragroides. 

 However, iu Peroj^hora they are foTiud in the duodeni;m and not in the 

 oesophagus and rectum. Moreover, I cannot make out that they are con- 

 nected with the cilia, or that there are an^' jirotoplasmic filaments running 

 down into the cells from them. 



