428 PHYSIOLO.GY AND MORPHOLOGY OF ANIMALS. 



tubes, branching and becoming more numerous, but the 

 branches lie parallel, and give rise to a radiating ar- 

 rangement. In the cortical portion, on the contrary, 

 the tubes are much convoluted, and finally terminate each 

 in a vesicle, which is filled with a tuft of capillary blood 

 vessels, looping round and connecting with an arteriole 



on the one ha?id and with a 

 veinlet on the other (Fig. 

 298). Blood vessels are 



Fig. 298. — Uriniferous tubules : m, 

 Malpighian corpuscles ; gl, glom- 

 erules. 



Fig. 299. — Uriniferous tubule : ut, 

 with its Malpighian corpuscle and 

 glomerule ; a, arteriole ; v, veinlet. 



also abundantly distributed among the tubules. These 

 terminal vesicles are the Malpighian corpuscles, and the 

 contained vascular tufts glomerules. 



Now, as in all eliminative organs, so here the whole 

 is lined throughout with epithelial cells (Fig. 299). The 

 epithelial membrane passes from the surface up the ure- 

 thra into and lines the bladder; from the bladder it 

 passes up the ureters and covers the pelvis. It then 

 passes up and lines the tubules and their terminal vesi- 



