STUDIES ON EARTHWORMS. 251 
series of reniform glands in the posterior part of the tract. 
Typheus (37) possesses lobed glands on the middle region of 
of the intestine. 
The sacculated portion of the intestine appears to be similar 
in all these worms, and is continued to near the end of the body 
when the typhlosole disappears, and the region is called rectum. 
The structure of the glands, whether they occur on the 
cesophagus or on the tubular intestine, is very similar in 
some of those that have been investigated. 
Claparéde (11) has described and figured a section of the 
cesophageal gland of Lumbricus, where it consists of nu- 
merous alternate blood-vessels and glandular tubules placed 
radially. 
Perrier describes the “‘ glandes de Morren” of Urocheta 
as having the same structure, but his figure does not quite agree 
with the text, as he figures no blood-vessels. In Titanus the 
gland has the same structure [and I shall show that in a 
worm (Microcheta), to be described further on, the struc- 
ture of the intestinal gland resembles that of the cesophageal 
gland of Lumbricus’ very closely]. But the various ceso- 
phageal glands in Perichzta each have a distinct structure, 
and none seem, from Perrier’s figures, to resemble the above- 
menticned glands. 
In all the above glands (except Pericheta) carbonate of 
lime has been found; usually solid, but sometimes in the form 
of a milky fluid. Hence we have analogous glands in various 
regions of the alimentary tract, and in different somites. So 
also the gizzard occurs in different somites. Perrier has 
suggested that these may not only be analogous but even 
homologous organs: the worm being made up of somites, 
each of which somites was originally exactly alike, in one somite 
of one worm a part of the alimentary tract becomes a gizzard, 
whilst in a second worm the modification occurs in a different 
somite. But each of these gizzards is a modification of an 
originally homologous organ, therefore the gizzards are homo- 
logous. In the same way the glands are modifications and 
swellings at different parts of the alimentary tracts, which were 
