A CONTRIBUTION TO THE ANATOMY AND DEVELOPMENT OF THE 

 POSTERIOR LYMPH HEARTS OF THE TURTLES. 



By Frank A. Stromsten. 



This paper is submitted as a preliminary report of the results ob- 

 tained by the writer in the study of the lymphatic system of the turtles. 

 While the anatomy of the lymph hearts has been so carefully and accu- 

 rately described in the sea turtle by Mtiller (1839) and in the large land 

 turtles by Fritsch (1874), their development, as far as is known to the 

 writer, has never been studied. 



Recently, the most general interest has been attached to the develop- 

 ment of the lymphatics in general. But the results obtained have been 

 by no means in accord. On the contrary, the most divergent conceptions 

 have arisen through the study of the mammalian type alone. It has 

 therefore seemed to the writer desirable to refer to a more generahzed 

 type of vertebrate, in the hope that some key to the divergent results 

 noted might be found. Accordingly, studies have been carried on for 

 several years upon reptilian forms, particularly the Chelonia. In the 

 present paper it is proposed to consider only the posterior lymph hearts 

 of the turtle, reserving the fuller treatment of the entire lymphatic 

 system for a later paper. 



Several years ago,^ while investigating the fate of the subcardinal 

 and postcardinal veins in the box turtles, the writer was interested in 

 noting the formation of a pair of rather large, muscular-walled sacs in 

 the subcutaneous mesenchymal tissue of the postiliac regions. These 

 spaces, which proved to be the posterior lymph hearts, seemed to be 

 intimately related in their development with certain changes in the first 

 two or three coccygeal branches of the postcardinal veins. It was not 

 possible at that time to complete the study of these interesting organs. 

 The work was again taken up, however, in the fall of 1908, and has been 

 carried on, as class-room duties permitted, ever since. 



METHODS AND MATERIALS. 



The work for the most part has been done in the laboratories of 

 animal biology of the State University of Iowa. I wish here to express 

 my thanks to Prof. Gilbert L. Houser, director, and to other members 

 of the Laboratory staff for suggestions and aid in collecting material for 

 the anatomical studies. The embryos of the loggerhead turtle {Thalas- 

 sochelys caretta), used for the study of the development, were collected 

 by the writer during the summer of 1907 at the Marine Laboratory of 

 the Carnegie Institution of Washington at the Dry Tortugas, Florida. 



1 American Journal of Anatomy, vol. 4, 1905. 



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