192 



Transactions of the Royal Society of South Africa. 



of the mantle-cavity is covered with numerous dark spots on a light grey 

 ground. In some cases these spots are nearly black ; in others they are 

 lighter and only clearly visible near the mantle-edge. 



The kidney is long and narrow and extends forwards from above the 

 heart to the mantle-edge just below the pulmonary orifice, where it curves 



35 36 



B 



Text-fig. 24. — Isidora (Physopsis) globosa (Morel.), Lorenzo Marques. 



A. Representative teeth from the radula ; X 400. 



B. Roof of mantle-cavity seen from within, showing kidney, etc. (slightly diagram- 



matic) ; x7. 



downwards, and then abruptly bends round and runs back above its former 

 course to the renal opening, which thus faces backwards about 2 mm. 

 within the pulmonary orifice (text-fig. 24, B). The kidney is therefore of the 

 same type as in Isidora. lameUata, Smith.* As in that species an afferent 

 renal vein runs back most of the way along the dorsal edge of the kidney, 

 while another vein conveying blood from the kidney to the heart runs along 

 its lower edge. This vessel receives a small pericardial vein just before it 

 reaches the heart, but the network of pulmonary veins which Pelseneer 

 shows beneath the kidney in /. lamellata is not apparent in the present 



* Pelseneer: op. cit., p. 370. 



