C. The reproductive and excretory systems. 



1. Of the male. 



(a) Examine and sketch — 



(1 ) The pair of testes, — smooth on ventral, lohulated on dorsal surface. 



(2) The much-coiled epididymes, — note the narrow connection between 



the testes and epididymes. 



(3) The coiled vasa deferentia (barely visible in young fish) terminating 



in an enlarged portion, the seminal vesicle. 



(4) The sperm sac lying external to the seminal vesicle. 



(5) The pair of elongated lobed kidneys on each side of the posterior 



part of the vertebral column, and external to the peritoneum, by 

 which they are covered. 



(b) Eemove the pelvic girdle (for future examination) without injury to the 



cloacal chamber. Cut open the cloaca, and note the large anal aperture 

 and the median urino-genital papUla. 



(c) Carefully cut along the papilla and expose the urino-genital sinus, and note 



in it the apertures of the ureters and of the sperm sacs. 



(d) Insert a bristle into each of these apertures, then remove the thick peri- 



toneum covering the kidneys, and note the ureters running along the 

 inner edge of the kidneys and communicating with them by numerous 

 efferent ducts, also the yellow inter-renal bodies situated between the 

 ureters and kidneys. 



(e) Cut open one of the sperm sacs, and note at its neck the aperture of the 



seminal vesicle. 

 (/) Examine (high power) the contents of the sperm sac, and sketch a sperma- 

 tozoon, noting its twisted elongated head and the long tail. 



2. Of the female. 



(a) Examine and sketch — 



(1) The ovaries. 



(2) The anterior portions of the oviducts, noting that the right and 



left unite in the middle line on the ventral aspect of the oesophagus, 

 and open into the abdoniinal cavity by a single median aperture. 



(3) The rounded oviducal gland, the secretion of which forms the case 



or " purse " for the ovum. 



(4) The posterior portion of the oviducts. 



(5) The kidneys. 



(6) The bi-lobed urinary bladder. 



(7) The delicate mesonephric ducts running forwards from the bladder. 

 (6) CarefuUy remove the pelvic girdle without injuring the cloaca, dissect 



off the peritoneum from the kidneys, and note the ureters on their inner 

 edge, and the yellowish inter-renal bodies. 



(c) Cut open the cloaca and note the apertures of the rectum and oviducts, and 



the central small urinary papilla. 



(d) Insert a blowpipe through the urinary papiUa and inflate the bi-lobed 



bladder. Cut it open and note the minute apertures of the ureters. 



