556 H. p. KJERSCHOW AGERSBORG 



is always built on the same fundamental plan as that of the 

 snaih The excretory system of M. leonina consists of a 

 bilateral structure with two main renal trunks, ureter, and renal 

 syrinx. The trunks extend anteriorly and posteriorly, dividing 

 into two sub-trunks, each of which pass into primary and 

 secondary branches. The anterior trunk divides much earlier 

 than the posterior, and the spread of the anterior bifurcation 

 is much larger than that of the posterior (PI. 35, fig. 60, 

 Ah, Ph). 



(2) The Ureter. 



The ureter (PI. 35, fig. 60, V) follows the intestine very 

 closely and empties a little to the anterior and left side of the 

 anal opening. This corresponds to Pelseneer's description (vide 

 Lankester, 1906), where it is recorded that the external opening 

 of the kidney is situated near the anus and sometimes the tw'o 

 open together into a sort of common cloaca, as may be seen 

 in Gymnosomata and in certain Pulmonata, such as 

 Limax. In rare cases, he says, such as in the nudibranch 

 Janus, the excretory aperture is distant from the anus. 

 The anterior bifurcations of the renal organ (Ah) extend just 

 beneath the pericardium with one sub-trunk on each side of 

 the aorta. The posterior renal trunk sends its branches among 

 the hepatic arborizations and connective tissues in the posterior 

 region of the animal, caudal to the ureter and the intestine. 



(3) The Kenal Syrinx. 



On the side of the ureter, midway between the junction of 

 the ureter to the renal trunks and the ureteric pore, is a bilobed 

 and somewhat convoluted whitish body which empties into the 

 ureter (PI. 35, fig. 60, Bs). This body is described by Hancock 

 (1865) as the pyriform vesicle ; von Jhering (1876) as the ' Peri- 

 cardialtrichter ' ; Bergh (1884fl) as renal syrinx that drains the 

 pericardial chamber. The renal syrinx is quite peculiar in 

 structure (PI. 35, figs. 61, 64, 67). In sections, it is shown to be 

 extensively plicated, but its walls are not muscular as observed 

 by Hancock (1 865) on T r i t o n i a h o m b e r g i i . The plicae are 

 strongly ciliated. The cilia of the individual cells are kept 



