406 Mr. G. C. Uobson on fJi& 



3. The iinnary cavi/i/ (" Urinkammer ") resembles tliat 

 found in the Paluclestrinicl'io. It ramifies among the 

 other organs, and is lined by a characteristic epithelium 

 composed of vacuolated cells with basal nuclei. 



Fig. 3. 



11. nosojAora {-^^ hoiu. imra. X \ oc). 

 Part of trabecular area of kidney. 6 = blood-spaces. 



TV. Circulatory System. 



The prricnrdinm is situated in the usual position. No 

 trace of a reno-jiericardial aperture was found, though it is 

 not certain that it is absent. 



The auricle and ventricle are normal. The latter is very 

 muscular and its cavity is traversed by numerous muscle- 

 fibres. Some indication is seen of an auriculo- ventricular 

 valve. 



The distribution of anterior and ])osterior aortae is normal, 

 the anterior running forwards over thereof of the pericardium 

 for some distance, tlien accompanying the oesophagus to open 

 into the cephalo-pedal sinus. The posterior aorta runs 

 backwards between the stomach and intestine. It would 

 appear that the portal vein enters the pulmonary vein before 

 tlie latter reaches the auricle ; but it is impossible to be abso- 

 lutely certain of this point. 



The cephalic and pedal portions of the anterior [cephalo- 

 Ijedal) sinus are incompletely separated by a horizontal 



