532 MR. T. H. BURLKXD ON THE UROGENITAL [Mar. 1, 



Receptaculum Seminis. 



This is a diverticulum situated ventral to the oviducts and 

 between them and the rectum. Its lining is glandular and it 

 opens into the urogenital sinus by a median opening in front 

 of the oviducal openings. The rod-like chitinous structure 

 present in all adult females is absent, and so has not yet been 

 secreted by its lining. 



Urogenital Sinus. 



This structure is well-marked in the young female : it receives 

 in front the opening of the " receptaculum seminis," then the 

 two oviducts open laterally further back, but a little in front of 

 the median smaller aperture of the urinary bladder. The sinus 

 opens on a median papilla situated a short distance behind the 

 anus, and l'eminds one of the urogenital aperture of the male 

 in appearance and position. 



In the further development of the female the urogenital sinus 

 opening gets larger and larger until the sinus is represented in 

 the adult merely by a depression with two deep pouches bordering 

 the oviducal openings a,nteriorly. 



The anus and abdominal pores do not differ from the condition 

 found in the adult. 



A young female Ccdlorhynchns I examined by means of sections 

 (kidney lent to me by Prof. W. 1ST. Parker) showed the same 

 general arrangement of the urogenital organs. 



The ovaries are comparatively short and the kidney extends 

 further forwards. The oviducts have a single median opening 

 into the ccelom, a uniform diameter throughout, with no swollen 

 uterine portion at this stage, and open separately immediately 

 dorsal to the anus into a distinct cloaca. There is no sign of a 

 " receptaculum seminis " or urogenital sinus. The abdominal 

 pores are imperforate as yet. 



The kidney possesses glomeruli throughout : it is at this stage 

 of uniform section, and the main ureter on each side receives 

 about four small ducts from each half of the kidney in front ; 

 the remaining five to seven small ducts from each side are 

 posterior and enter the bladder along with the main ureter. 



Summary and Conclusions. 



The following points relating to the above description deserve 

 special notice : — 



(1) The urinary organ of the young male differentiates in 

 the adult into anterior paired Leydig's glands and posterior 

 unpaired kidney. 



(2) The glands of Leydig do not function as a renal organ as is 

 shown by their histology and the contents of their ducts ; further, 

 the condition of the spermatozoa at intervals in the long coiled 

 sperm-ducts (Leydig's ducts) renders it probable that the 



