818 
WILLIAM F. ALLEN. 
lymphatic vessels (see Fig. 4 a) these vessels were found to 
■terminate ventrad in the great lateral sinus, and on the level 
with the top of the mucous sacs they sent inward a branch to 
•communicate with the ventral or inferior longitudinal haemal 
lymphatic trunk. 
Ventral or Inferior Longitudinal HEemal Lym- 
phatic Trunk (Fig. 4 a, V. L. Hse. T.). — Is a rather con- 
spicuous vessel, though considerably smaller than the superior 
longitudinal haemal lymphatic trunk. It is situated midway 
between the caudal vein and a longitudinal row of mucous 
sacs. I have not studied this trunk anteriorly, but posteriorly 
it terminated in the anterior fork of the common longitudinal 
haemal lymphatic trunk directly in front of the lateral pro- 
cesses of the median ventral cartilaginous bar. The short 
distance in which I have observed this trunk shows it to be 
much larger posteriorly than it is anteriorly ; hence the flow 
of lymph is probably caudad. Small communicating vessels 
have already been described coming from the intersegmental 
lirnmal vessels. The main branches received, however, are 
segmental vessels that follow the surface of the anal or 
ventral fln-rays between every two mucous sacs and commu- 
nicate ventrad with the ventral veno-lymphatic trunk. These 
vessels are not lettered, but are clearly shown in Fig. 4a, and 
may be simply dorsal continuations of the ventral or anal flu- 
ray vessels. Posteriorly in the 20 cm. series a direct connec- 
tion with the superior longitudinal hmmal trunk was noted 
together with several communications from a rather large 
sinus situated on the lateral surface of the last two mucous sacs. 
This reservoir (Fig. 4 a, d.) is quite conspicuous in the 
10 cm. series, for it covers a large part of the lateral surface 
of the last two mucous sacs. Dorsad it has at least two con- 
nections with the inferior longitudinal hmmal lymphatic trunk, 
cephalad it ends in rather loose lymphoid tissue, ventrad it 
has several communications with the great lateral sinus, and 
oaudad it tapers down into a rather long stem that termi- 
nates in the ventral veno-lymphatic trunk at the junction of 
•one of its connections with the lateral sinus. No similar 
