LYMPHATICS IN TAIL REGION, SCORP^NICHTHYS 6 



with an European firm. It did not, however, arrive until after 

 my paper appeared, and I was unable to gain access to another 

 copy. 



A year earlier Favaro published a most interesting paper on 

 the caudal heart of the eel, and as was the case with the previous 

 mentioned paper I was unable to gain access to this until quite 

 recently. The author finds the caudal heart of the eel to be a 

 lymphatic heart situated at the posterior end of the last vertebra 

 and to consist of two cavities. As I had long suspected the 

 first, the atrium cordis caudalis is said to be in communication 

 anteriorly with the longitudinal haemal trunk, tronco linfatico 

 subvertebrale, and posteriorly with the trunk from the tail. Both 

 openings are guarded by valves opening into the atrium. The 

 atrium is connected mesad with the second cavity, ventriculus 

 cordis caudalis, the orifice being guarded by valves opening into 

 the ventricle, and anteriorly the ventricle empties into the caudal 

 vein, the orifice, likewise having valves opening into the vein. 



Kellicott in his monograph on the vascular system of Ceratodus 

 does not allude to the lymphatics or subcutaneous system further 

 than to say that a pair of well developed lateral cutaneous veins 

 are found beneath the skin at a level with the lateral line. Poster- 

 iorly they are said to anastomose with the caudal vein and an- 

 teriorly they open into the subscapular veins. Kellicott likens 

 these vems throughout to the lateral cutaneous veins of Mustelus 

 as described by Parker. 



The recent studies of Sabin, Lewis, Huntington and McClure, 

 Hoyer, Knower, Baetjer, Heuer and Clark on the ontogeny of the 

 lymphatic system concede that the primary or deep seated lym- 

 phatics arise as sacs or hearts from transformed veins, and that 

 the superficial or secondary lymphatic system originates from an 

 endothelial sprouting from these sacs or hearts. Sala while 

 admitting the derivation of the lymphatic hearts or sacs in the 

 chick from the veins still holds to the old view that the ducts are 

 formed from the mesenchyme cells. Marcus states that the 

 segmental lymphatic hearts in the snake-like Amphibian, Hypo- 

 geophis, are formed from the coelom or body cavity epithelium and 

 not from veins. 



