274 WILLIAM BLAXLAND BENHAM. 
septa are slightly thinner than this third one, whilst the septa 
subsequent to these are much weaker. 
The Alimentary Tract.—The digestive tube consists of 
(2) Buccal region, (6) Pharynx, (c) Gsophagus, (d) 
Gizzard, (e) tubular intestine with gland, (f) sac- 
culated intestine, and (g) Rectum (Pl. XV, figs. 2 
and 3). 
(a) The Buccal region (B in the figure) immediately 
follows the mouth ; it is a short, thin-walled region, and seems 
to be slightly protrusible, thus bringing the muscular pharynx 
into direct contact with the food, which can then be clasped by 
this organ. This region seems frequently to be omitted in 
descriptions of Earthworms; it is certainly very limited in 
extent, but seems, according to Perrier (14), to be pretty con- 
stant, and its posterior limit is marked by the circumpharyn- 
geal nerve commissure. In Microcheta it only extends to the 
third annulus, i. e. through one somite. 
(6) The Pharyux (PA.) then follows, and, as in other 
worms, is a very muscular organ, and besides its intrinsic 
muscles is held to the body wall and first septum by numerous 
radiating muscles (7.m.), some of which are very thick. The 
pharynx does not quite reach the first septum, and thus only 
occupies somite 11 and part of somite 111. As arule the pharynx 
extends through four or five somites, but here the somites, 
although only two in number, are very long, and the pharynx 
has an extent of nearly one inch. The limit of the pharynx is 
often incorrectly stated, e. g. that of Lumbricus is put down as 
reaching to somite vii whilst really it extends only to the end 
of somite v; this error is due to the infundibulate shape of the 
septa. As for the vexed question of glands in the pharynx, 
which Perrier seems inclined to consider present, I could find 
none, either by dissection or by means of transverse sections ; 
Claparéde figures none in his paper on the histology of Lum- 
bricus (11). 
(c) The Hsophagus (Oe.) commences just in front of the 
first septum, and passes through the somites 1v and v. The 
wall is thin, and close in front of the septa through which it 
