l90l.] LEPIDOSIEEN AND PROTOPTEEUS. 48? 



sponge-work Avhich has been described pass in and out of the 

 kidney, the dorsal portion of the sponge-work being completely 

 imbedded in the kidney substance. In the breeding male the cavities 

 of the trabeculse are greatly distended and full of spermatozoa, so 

 that in the kidney of the male during the breeding-season we find 

 that region of the kidney which lies on the mesial surface of the 

 organ and ventral to the hilus traversed by large cavities packed 

 with spermatozoa. 



The most regular of these function as vasa eiferentia, and their 

 general relations may best be gathered from such a figure as I 

 exhibit (see fig. 1, Plate XXYII., which represents a reconstruction 

 of kidney and testis from longitudinal vertical sections, viewed from 

 its inner or mesial aspect). The vasa efferentia (V.E.) are seen as 

 irregular tubular structures which from their point of origin slope 

 forwards and dorsalwards. They pursue this direction for a 

 short distance until they come into proximity with a clump of 

 Malpighian capsules. They then break up into branches which open 

 into the Malpighian capsules. 8ome of the branches of the vasa 

 efferentia appear to end blindly, or are continued by very fine cavities 

 which I have not been able to trace throughout. The Malpighian 

 capsules in the adult Lepidosiren are arranged in chimps and a single 

 vasefferens may supply either a single capsule or more of the clump- 

 it may also send prolongations to capsules of other clumps. It is 

 noteworthy that the Malpighian capsules into which the vasa 

 efferentia open are, as is also the case with other capsules in the 

 same region of the kidney, lined by cubical epithelium instead of by 

 the fiattened form more familiar in adult animals. In the text- 

 figures 50 and 51 (pp. 488, 48y) I show sections through such 

 Malpighian capsules, in one of which the lumen of the capsule is 

 seen to be packed with spermatozoa. 



The communications between kidney and testis are confined to 

 the vesicular region of the testis and to the posterior portion of 

 this region. This has been demonstrated by the examination of 

 complete series of sections through the whole length of the genito- 

 urinary complex. In the specimen shown in Plate XXYII. fig. 1, 

 the vasa efferentia are confined to the posterior lialfoi the vesicular 

 region of the testis. They may, however, extend further forwards. 



In two specimens in which I have counted them, the number of 

 vasa efferentia numbered six and five respectively \ 



In the specimen in Plate XXVII. fig. 1, it will be noticed that 

 each one occurs roughly at the same level as one of the large 

 collecting-tubes opens into the kidney-duct. Their segmental 

 arrangement corresponds with that of the collecting-tubes. 



The spermatozoa finally reach the kidney-duct by the last few 

 of the collecting-tubes that drain into the duct. In the breeding 



' Ehlers found " one communication between testis and kidney-tubules" (no 

 doubt one of the vasa efferentia, which I have described) and also posteriorly- 

 several direct connections between testis and kidney-duct. This latter point I 

 have not been able to confirm — much as, for theoretical reasons, I should like 

 to have done so. 



