250 WILLIAM BLAXLAND BENHAM. 
somites, xix and xx; whilst behind this comes the sacculated, 
typhlosolar region, with thin walls covered externally by the 
large, yetlow ccelomic epithelium ; in this form the typhlosole 
is well developed, and, as usual, presents a blood-vessel in 
frequent connection with the dorsal trunk. 
In other forms the tubular portion has a greater extent; for 
instance, in Anteus it extends from about somite viit to xviiI, 
in Titanus from somite vi to xv. In Acanthodrilus, 
judging by Perrier’s figures, one species has none, in another 
this region extends to somite xx, and in Urocheeta as far as 
somite xv. In all cases where a structure is said to extend to 
a certain somite, it is understood to exist in that somite as well 
as in the preceding somites. 
In these forms cesophageal glands are absent, but their ana- 
logue seems to be frequently present in the form of one or more 
pairs of glands, which contain carbonate of lime, situated on 
the tubular region of the intestine. 
In Urocheta there are three pairs of such glands, elon- 
gated and ovoid, in somites vii, 1x, x; in Plutellus three 
pairs of glands of the same nature occur in somites X, XI, XII, 
but are reniform. 
In Titanus isa single pair of white, nearly spherical glands, 
in somite x11, which Perrier mistook for a part of the vascular 
system. He describes it as a “ventricle.” I have had the 
good fortune of dissecting a Titanus, and have seen distinctly 
the large openings of these glands into the intestine. 
One of the characteristics of the genus Pericheta appears 
to be the presence of a pair of elongated ceca, springing 
from the ventral surface of the sacculated intestine in somite 
xxvi or xxv. In P. Sieboldii, Horst, there are six pairs of 
ceca in somite xxvi. Although Perionyx resembles Peri- 
cheta in many points these czeca are absent in it. 
The typhlosole is usually a sub-cylindrical longitudinal 
valve produced by an involution along the dorsal wall of the 
sacculated intestine; but in Titanus this organ is flattened 
from side to side, whilst in Pontodrilus the vessel alone 
exists. Pleurocheta has no typhlosole and possesses a 
