STUDIES ON EARTHWORMS. 249 
The great development of these glands in Pericheta seems 
related to the extremely small size (? absence in some) of the 
nephridia. Perrier has suggested that they act in some way 
as excretory glands, the excretion, however, being used as a 
digestive fluid, instead of being passed directly to the exterior, 
just as the liver of Vertebrates is in a way an excretory gland. 
The gizzard is present in all but Pontodrilus. The walls 
are very muscular, and the lining epithelium secretes a chiti- 
nous lining, which forms the crushing apparatus. 
The gizzard is situated very far back in Lumbricus, where 
it occupies somites xvii and xvi. Here it is quite behind all 
the genital organs even behind the male pore. In Perionyx 
the gizzard is in somite x11, in the same somite as the posterior 
seminal reservoir. 
In all the other forms it is in front of the seminal reservoirs, 
being usually in somite vi (Anteus, Titanus, and Plu- 
tellus), or in somite vir (Urocheta, Eudrilus, and 
Rhinodrilus). In some cases it occupies only one somite, 
in others it occupies more than one. In Anteus the anterior 
septa are very thick and infundibuliform, covering the gizzard; 
but frequently the septum immediately in front of this organ 
is thinner than the neighbouring ones. In Pericheta the 
somite 1x contains the gizzard. Digaster is so named from 
its possessing two gizzards, the anterior being in somite v, the 
posterior in vu, the portion of the alimentary tract between 
them being the second cesophagus. A further complication I 
have found in a worm from St. Thomas’s, where there are 
three separate gizzards. Moniligaster again has a gizzard 
in somite vi of the usual form, whilst an elongated gizzard 
occupies somites x11I to xx1t inclusive, being constricted into 
four portions. Here, therefore, the first gizzard is in front of 
the true genital organs, the second being behind them. 
The Intestine following the gizzard is frequently separated 
into two regions, the portion directly behind the gizzard being 
the ‘ tubular,” and following this a more or less “ sacculated ” 
region where the typhlosole is developed. 
In Lumbricus this tubular portion occupies only two 
