460 
PROFESSOR J. STEPHENSON AND DR BAINI PRASHAD ON 
The layer of rodlets (Stabchen) is well known to occur not uncommonly on columnar epithelium, 
but its significance is apparently not very clear. Schafer (23) says : “ Their free surface (the 
description is of columnar epithelium in general) is covered by a thick striated border, which may 
sometimes become detached in teased preparations.” Gurwitsch (11): “A general occurrence in 
absorptive cells and excretory cells is the possession of a fringe of bristles, — e.g. in the epithelial 
cells of the gut which take up fat, — but not in secretory cells; it may be inferred that the object 
is to increase the surface, though this is not at present demonstrated.” Schneider (25) in the 
section entitled “Nahrzelle (Nutrocyte),” which he defines as epithelial cells, mostly pertaining to 
the enteroderm, always with extracytal differentiations (cilia, flagella, rodlets), seldom with 
intracy tal (muscular fibrillse), function nutritive : ' ‘ The rodlets are short stiff structures, held 
together by a homogeneous substance, in which clear pore-like intervals are often seen ” ; in the 
figures they appear as fine lines between -rectangular blocks of clear intervening substance; and 
it would seem that what we have called rodlets in the description of the epithelium of Eutyphoeus 
corresponds rather to these blocks — at any rate we have been unable to see the fine bristles between 
these blocks of lightly-staining substance. He adds : “ In many cases it seems as if the cementing 
mass between the rodlets were itself of importance for absorption.” 
Heidenhain (13) states that the “brush-border” (Biirstensaum, also called the Stabchenorgan) 
is present, as is well known, both in absorptive- and secreting cells (thus differing from Gurwitsch); 
its typical representative being the intestinal epithelium of Vertebrates, the best investigated 
epithelium of this type ; the border of the kidney cells has also been much discussed ; numerous 
other objects possess the border, but have only occasionally been described and figured; it is 
found, for example, in the polynuclear cells of the decidua epithelium of the rabbit, and in the 
mantle epithelium of snails beneath the shell. The rodlets possess in general, like the cilia, basal 
corpuscles, by means of which they are. implanted in the surface of the cell ; they have been 
compared by Frenzel to. the basal non-mobile somewhat thicker portions of cilia (Fussstabe) 
— which however do not occur in Vertebrates, and are especially seen in the intestinal tract of Worms 
and Molluscs; Joseph is said to have shown that in the intestine of the earthworm the epithelium 
is ciliated ventrally, while dorsally, on the typhlosole, it has ,the brush- border ; in the transition 
zone the series of “ Fussstaben ” pass into the brush-horder without break — and one may conclude 
therefore that in the ciliated part of the tract the immovable basal part of the cilia replaces 
functionally the rodlets, and has the same relation to absorption as these (what this is is not stated) ; 
Heidenhain, however, does not admit a morphological homology. Between the Fussstaben there 
is sometimes a thin material, stainable and sometimes simulating a pore-cuticle ; this may also be 
the case in the brush-order, in the intestine and kidney. 
The figures of the rodlets in Heidenhain show (1) a layer of very numerous lightly-staining 
threads, not all the same length, resembling cilia, with very marked basal corpuscles; or (2) 
apparently thicker rods, strictly parallel, and all the same size, with small intervals between them 
(the condition in Eutyphoeus, as described below) ; or (3) relatively shorter rods, very close together. 
There is no figure like that in Gurwitsch — fine needle-like rods with a relatively large amount of 
cementing substance staining much more lightly in between them ; but the figures of the basal 
portions or Fussstaben of cilia do show that condition — the spaces being filled up with an almost 
clear, slightly granular matter. 
The (Esophagus in the Genus Pheretima (Figs. 1, 2). 
In the widely distributed P. hawayana the oesophagus is swollen segmentally in 
segments x— xiii, and constricted intersegmentally. The swellings are approximately 
globular ; in horizontal longitudinal section the anterior may be seen to bulge 
slightly forwards, and the hindmost slightly backwards. 
In these segments the epithelium (fig. l) is thrown into prominent transverse 
folds, which may take up almost half the diameter of the tube, leaving only a narrow 
