B. F. Kingsbury 105 



rangement of the capsides in regard to the collecting duct, three general 

 types of structure were found: (1) with a longitudinal collecting duct 

 in the center and the capsules radially arranged, (2) with the longi- 

 tudinal canal superficial and the arrangement of the capsules fan-like, 

 (3) the capsules short (more spherical) and terminating the divisions of 

 the richly branched collecting duct. Between these extreme types, 

 however, are transitional forms even in different parts of the same testis, 

 as, for example, the central longitudinal canal becoming superficial. 

 Hoffmann extended Speu gel's work, adding also to the knowledge of 

 the development of the organ. La Valette St. George, 76, in his well- 

 known paper, carried the analysis of the structure a step farther. The 

 testis is made up of " tubules " (capsules of Spengel), which may be 

 hollow or not, and these " tubules " are made up of " follicles " enclosing 

 " spermatocysts "—clusters of cells formed from a single original cell by 

 division. 



Meves recognizes the occurrence of the " cysts," which are arranged 

 together in the form of a " thick- walled vesicle enclosing a central 

 cavity. . . . Therefore, it is not proper to speak of tubules (referring to 

 La Valette) here." These vesicles again are the tubules of La Valette, 

 the capsules of Spengel. 



Far more appropriate seems the designation of " lobule," which will 

 be the term employed in this article. These divisions or lobules, sepa- 

 rated from each other by connective tissue, are the structural units of 

 the organ, and each is connected with the central collecting duct by a 

 short tubule. Further, their homology with the lobules of the mam- 

 malian testis seems probable. Hoffmann has found that the collecting 

 duct with its branches is developed from the tubules of the mesonephros, 

 suggesting, therefore, their homology with the rete testis and vasa recta. 

 The lobules of the Amphibian testis are not differentiated into tubules, 

 though in some forms (e. g., Bufo) the structure, of the tubule of the 

 mammalian testis is suggested. 



The testis of Desmognaihus combines the first and second of Spengel's 

 three types, there being a longitudinal collecting duct, which is centrally 

 located save at the ends of the organ, where it becomes nearly or quite 

 superficial. About this collecting duet the lobules are placed radially, 

 each connected with it by a short cord of cells whose arrangement in 

 the form of a tubule is more or less evident. The form of the testis 

 varies greatly with the season of year, due to the changes in the sperma- 

 togenetic cycle. In general, it is enlarged in the center and tapering at 

 both ends, the enlargement and shape of any part being caused by the 

 state of development and therefore size of the component lobules. 



