464 
PROFESSOR J. STEPHENSON AND DR BAINI PRASHAD ON 
half of the layer is close and granular, of the deeper half is rather clearer. 
Outside the epithelium is an almost continuous blood sinus ; the muscular layer is 
very thin. 
In three specimens of this species from the Ross Andamans, sectioned by one of 
us some time ago in the course of systematic work, the rodlets in segment x appear 
as if beginning to be transformed into cilia ; they slope backwards, and have no 
longer the regular palisade arrangement. In xi they become typical cilia — thin wavy 
filaments, 20 p, or perhaps much more in length ; they are especially marked at the 
place where the narrow oesophagus widens to form the intestine, at septum 11/12 ; 
here they form a tuft which projects backwards from the narrow neck into the 
following wider portion. Further back, in the intestine, the epithelium is covered 
by a thin cuticle-like layer, which, however, is not homogeneous, since it stains in 
its basal half, though the superficial part is colourless. 
The Glands in the Genus Octoch^etus (Figs. 5, 6). 
Beddard in his Monograph (l) gives a short description of the condition in the 
young 0. multiporus. The gland is single, and projects forwards in the mid-dorsal 
line on the oesophagus ; where it joins and opens into the oesophagus it begins to 
extend laterally as well, coming to cover the whole surface of the gut except in 
the mid-ventral line. The lining epithelium is arranged in numerous folds, some 
penetrating further towards the lumen than others. The gland epithelium is in 
general cubical, and therefore lower than the columnar epithelium of the oesophageal 
tube ; but the free edges of the folds are thicker than the rest, since the cells are here 
more columnar ; in the peripheral portions of the gland the cells are ciliated. 
We have examined 0. barkudensis (27) in transverse sections. Here the glands 
are paired, large, lobed and asymmetrical, occupying segments xv and xvi ; but the 
openings of the two glands are at the same level. The glands are essentially diver- 
ticula of the oesophagus, containing a great number of thin lamellae arising from the 
wall and projecting into the interior, ending in a free edge near where the lumen of 
the gland debouches by a narrow duct into the oesophagus (fig. 5). 
In the peripheral parts of the glands there are numerous “bridges” between 
neighbouring lamellae ; and, though the specimen is not injected, and for the most 
part the enveloping sinus is not marked, some of the lamellae are distended with 
blood — a sheet of blood between two layers of epithelium. 
The cells of the epithelium of the lamellae are for the most part much flattened, 
and the lamellae extremely thin ; in the periphery of the gland the cells are more 
cubical, transparent, sometimes filling up the peripheral end of the crypt between 
two adjacent lamellae. In the crypts are small transparent crystalline-looking 
particles, probably calcium carbonate, which appear to have been formed within the 
cells of the peripheral portions of the lamellae ; these cells are often much vacuolated, 
