DEVELOPMENT OF SUPRAPERICARDIAL BODY 



401 



contraction and expansion of the muscles of the mouth and 

 pharynx. If the pressure be low the vessels carry lymph and 

 if high they carry blood. Such a primitive arrangement of the 

 circulation is common in fishes, and, although I have not had 



Fig. 18- Transverse section of the suprapericardial both' of an adult, passing 

 through the pharyngeal diverticulum, Ph.d.; M.cb., musculus coracobranchialis; 

 P.c, pericardial cavity; C.c, ceratobranchial cartilage; Ph.a., pharyngeal ar- 

 tery; vasa lymphatics in solid blackjvenae lymphaticaein parallel diagonal lines; 

 alum hematoxylin. X 35. 



opportunity to study the circulation by injection of fresh speci- 

 mens, I feel certain this condition is present in the supraperi- 

 cardial body. 



In the newborn fish the large venae lymphaticae are very 

 numerous and form a rich plexus which so completely envelopes 



