526 WILLIAM BATESON. 
where they are united in a plexus of larger vessels (ep., figs. 
95—97). The outer cells of the gland are modified to form a 
peculiar tissue (fig. 97). They are large cells, which stain 
deeply and have a nucleus usually on their outline. The cells 
standing on the capillaries contain some yellow granules, and 
larger granules or even masses of them are to be found in the 
spaces surrounding them. 
The gland of the living B. salmoneus is light green in 
colour. 
The nature of these glands is entirely obscure. These 
yellow granules occur amongst nearly all the mesoblastic 
tissues. In B. Robinii (collar) they may be found in the 
fresh state, presenting the appearance shown in fig. 100. They 
are never crystalline. 
An attempt was made to investigate the chemical nature of 
these bodies, but with only negative results. They may, per- 
haps, be excretory, and it is possible that they are more or less 
removed by the proboscis pore and collar funnels respectively. 
This does not explain their presence in large masses in the 
trunk body cavity (v. fig. 93, a), from which no pore has been 
observed to open. Occasionally granules of this character 
occur in the ectodermic structures, suggesting that they are a 
product of the activity of all the tissues. 
The proboscis pore was shown to arise at two gill-slits 
as a small vesicle in the skin of the proboscis stalk upon the 
left side (v. fig. 34) ; at three gill-slits it acquires an opening 
to the exterior, and at four gill-slits its tissue fuses with the 
lining of the left posterior horn of the anterior body cavity. 
(v. fig. 99), placing this cavity in communication with the 
exterior. 
In B. Kowalevskii this pore is permanently on the left 
side of the body; in B. minutus, &c., it is median. [In my 
first paper on the “ Later Stages,” &c., p. 25, last line but one, 
B. minutus was written by mistake for B. Kowalevskii.] 
The collar funnels arise as thickenings in the outer wall 
of the arterial cavity opposite the opening of the first gill-slit 
(v. fig. 101). These thickenings soon become perforated 
a 
