234 George S. Huntington and Charles F.. W. McClure. 
development of the cranial bend, is further condensed and appears 
relatively shortened by the further development of the jugular 
promontory. 
The dorsal tributaries of the precardinal are condensed, and 
approximated to each other. The more numerous individual 
branches of the earlier stages are replaced by larger single trunks 
representing the three typical anterior sets, tributaries 1, 2, and 3. 
Dorsal tributary 4 of the earlier stages now terminates, for the 
most part,inthe promontory at the promontorio-precardinal junc- 
tion. It (4) may be in part or entirely taken up in the subsequent 
veno-lymphatic formation, or it may be permanently retained as a 
somatic branch, in which case it forms the first of a series of 
somatic tributaries entering into the dorso-medial aspect of the 
promontory, or, finally, it may exhibit distinctly both veno- 
lymphatic and dorsal somatic characters, with numerous trans- 
verse anastomoses between the two elements. 
In fact, all of the fundamental processes involved in veno- 
lymphatic development, as described above under Analysis of 
Developmental Stages in the Formation of the Jugular Lymph 
Saes, are represented in one or the other of the above mentioned 
series, and may be summed up as follows: 
- (1.) Progressive enlargement and caudal extension of the 
jugular promontory. (2) Increase in secondary capillary forma- 
tion and resulting increase in the reticulated and fenestrated dorso- 
lateral circumference of the promontory and the postcardinal vein, 
and consequently an enlargement of the dorsal veno-lymphatic 
plexus. (3) The establishment of the anlage common to 
the primitive ulnar vein and the primitive ulnar veno-lymphatie. 
(4) The transferal of the main blood current in tributary 4 from 
the precardinal vein to the promontory through the secondarily 
formed para-precardinal channel. (5) Separation of precardinal 
tributary 4 and its associated para-precardinal channel into a 
veno-lymphatie and a dorsal somatic component, (6) Sepa- 
ration of the precardinal tributaries 1, 2 and 3 into their 
veno-lymphatie and dorsal somatic components. (7) Estab- 
lishment of the cephalic and caudal divisions of the ventral 
veno-lymphatic plexus. 
