Genito-urinary Apparatus of the Male Porpoise. 117 



but slightly larger in thickness. The average human kidney 

 is also distinctly smaller than the kidneys of the present 

 specimen of the porpoise, which, although adult, was not 

 a large specimen of its kind. 



We have thought it advisable to revise the description 

 of the course pursued by the ureter in its passage from the 

 kidney to the urinary bladder, because former accounts have 

 not recognised the presence of a pelvic cavity as a feature of 

 the abdominal cavity of Cetacea. 



Each Ureter passed backwards (i.e., caudally) from the 

 hinder end of its own kidney, lying between the peritoneum 

 and the fascia covering the muscles of the dorsal wall of the 

 abdomen, and situated about 2'5 cm. external to the attached 

 base of the mesentery. Having approached near to the inlet 

 of the peritoneal pelvic cavity, the ureter inclined slightly 

 towards the mesial plane, and crossed superficial to (i.e., upon 

 the ventral aspect of) the hypogastric artery. Thereafter 

 continuing its course towards the urinary bladder, it entered 

 between the peritoneal and fascial walls of the pelvic cavity, 

 being meantime crossed by the vas deferens. Travelling 

 onwards, towards the ventral aspect of the pelvic cavity, the 

 ureters pierced the lateral aspects of the urinary bladder, 

 obliquely from before backwards, there being nearly 2 cm. 

 of each ureter buried in the substance of the wall of the 

 bladder. Under cover of the vesical mucous membrane, the 

 two ureters coalesced, and thus they presented a single mesial 

 opening or mouth into the interior of the bladder. This 

 orifice was situated within a distance of 1 cm. from the outlet 

 of the bladder. According to Daudt, the openings of the two 

 ureters "sind bald naher aneinander, bald weiter voneinander 

 entfernt, dies schwankt zwischen 4 und 9 mm." 



The Urinary Bladder was situated upon the ventral aspect 

 of the abdominal and pelvic cavities. We found it empty 

 and contracted, thereby presenting dorsal and ventral sur- 

 faces. The dorsal surface (directed towards the abdominal 

 and pelvic cavities) was clothed by peritoneum which formed 

 false ligaments along the apical and lateral margins of the 

 viscus. The ventral or pubic surface was devoid of peri- 

 toneal covering, and lay in contact with the ventral aponeu- 



