DEVELOPMENT LYMPHATIC SYSTEM IN AMNIOTES 285 



periphery. Instead, Fedorowicz first establishes the independent 

 ontogeny of the lymphhearts and of the extracardiac early lym- 

 phatics. Then these are brought together, their lumina con- 

 necting, not directly, but through the intervention of a some- 

 what complicated system of cellular strands which develop, later 

 than the extracardial hanphatics, within the cavities of the heart, 

 acquire an intercellular lumen and then secondarily connect with 

 the lumina of the extracardial lymphatics. All this speaks of a 

 most determined effort on the part of the independently devel- 

 oped extracardial lymphatics to gain entrance, proceeding cen- 

 tripetally, into the interior of the lymphheart. And yet, imme- 

 diately following his account of these events, and after men- 

 tioning that the early Ijanphatic plexus often exhibits a definitely 

 radiating arrangement, he proceeds to state: "Es ware kaum 

 moglich anzunehmen dass diese Gefasse von den beiden longi- 

 tudinalen Lymphgefassen des Schwanzes, der V. lymph, longit. 

 dors, et ventralis, nach dem Herzen zu so regelmilssig zentripetal 

 wachsen konnten." It seems difficult to see why, once accept- 

 ing the idea of 'growth' in a continuous line, the same should 

 not take place in either direction, from the center toward the 

 periphery, or reversely from the periphery toward the center. 

 Nor can I see any reason why such growth should be more 

 'regelmassig' if directed centrifugally. Fedorowicz assmnes two 

 possible points for starting his theoretical growth, one centrally 

 from the 'he^rt,' the other peripherally from the ''dorsal and 

 ventral longitudinal lymphatic trunks," and decides in favor of 

 the former apparently on the ground that it would be impossi- 

 ble to conceive of growth taking place so 'regularly' in the re- 

 verse direction. This is pure assumption, and not evidence. 

 Any vertebrate embryo can 'grow' in any of his parts just as 

 'regularly' from the center toward the periphery as from the 

 periphery toward the center, as far as anj^ biogenetic law is 

 concerned of which I have knowledge. The fact that the embryo 

 'grows,' or more euphemistically 'develops,' in either of both of 

 these directions, in establishing his main static developmental 

 lines, has nothing to do with the ontogeny of the embryonal 

 anlages which enable these processes to take place. It seems 



