32 WILLIAM F. ALLEN 



longitudinal liaenial lymphatic trunk. From this point cephalad, 

 this longitudinal trunk may be a single canal or it may have re- 

 solved itself into several, in which case they appear in transverse 

 section like rather large cavities in the spongy connective tissue 

 supporting the blood vessels. In this trunk the corpuscles are- 

 extremely scarce, and as was noted for the other lymphatic trunks, 

 the red greatly outnumber the white. Upon entering the body 

 cavity this trunk takes on more the form of a sinus, which fol- 

 lows the aorta, cephalad, between the vertebral column and the 

 kidney, and where the kidney separates into right and left lobes 

 at the insertion of the retractor muscles of the pharyngeal bones, 

 it joins the great abdominal sinus, situated below the kidney. 

 In an earlier paper (pp. 62-3) the cephalic termination of this 

 sinus has been fully given. 



From the tail to the body cavity the longitudinal haimal trunk 

 received a htemal lymphatic trunk (fig. 4a, Hoe. T.) from between 

 each two segments, which amounts to, one for each segment. 

 Exactly the same correlation was established between these haemal 

 lymphatic vessels and the blood vessels as was shown between the 

 neural lymphatics and the neural blood vessels. Along the an- 

 terior surface of a haemal spine there traveled a haemal lymphatic 

 vessel and a haemal artery, and along the next spine a lymphatic 

 vessel and a vein, this relationship being even more constant than 

 was the case with the neural vessels. In the region of the anal 

 fin the haemal lymphatic vessels arose from two branches from be- 

 tween the extrinsic and intrinsic muscles of the fin, which occa- 

 sionally anastomose with the corresponding branch ahead or be- 

 hind, thus forming a short longitudinal trunk on the side of the 

 base of the fin. These branches also collect the anal ray lymphatic 

 canals (fig. 4a, A.R.T.), which traverse the posterior surfaces of 

 the rays and gather a network from the fin membrane. Thus 

 formed a haemal lymphatic trunk crosses a pair of intrinsic anal 

 ray muscles, but upon reaching the apex of a haemal spine it does 

 not send off a connecting branch to the adjacent haemal trunk, 

 to form a secondary ventral longitudinal trunk. Its course was 

 then dorsad along the haemal spine, immediately distad of the 

 corresponding blood vessels, and entering the haemal canal it joins 

 the longitudinal haemal lymphatic trunk. 



