522 Mil. T. II. BURLEND ON THE UROGENITAL [Mar. 1, 



genital sinus by two apertures situated behind those of the 

 sperm-ducts (text fig. 42, tir.o.). 



Histology. —In section the kidney presents typical excretory 

 tubules (not so large as the tubules in Leyrlig's gland), with 

 numerous well-developed glomeruli in the dorsal region. More- 

 over, the ureters do not contain nucleated material such as is 

 found in the ducts draining Leydig's gland. 



Urogenital Sinus. 



The median rather narrow urogenital sinus receives the sperm- 

 duct and urinary openings at its front end, and passes dorsal to 

 the rectum to end in a flask-shaped, somewhat laterally com- 

 pressed structure, into the ventral wall of which the ends of the 

 MiUlerian ducts pass close together. The sinus opens on the apex 

 of a median papilla behind the anus, and between the bases of 

 the posterior claspers. Hence the cloaca, usually found in male 

 Elasmobranchs, is absent in Chimcera. 



Two abdominal pores situated on the latero -posterior margins 

 of the anus put the abdominal cavity in connection with the 

 exterior. 



Mullerian Ducts. 



Mere traces of the Mullerian ducts are to be found persisting 

 in most adult male Elasmobranchs, but the male Chimcera 

 possesses them in the most perfect condition. 



They appear as narrow tubes running between testis and coiled 

 sperm-duct of each side, and further back, on the outer border of 

 the sperm-vesicle ; they end blindly behind in the wall of the 

 urogenital sinus, but open into the ccelom anteriorly by slit-like 

 openings, quite an inch apart, situated on the posterior surface of 

 the wall dividing the pericardial cavity from the general body- 

 cavity. No evidence was given by either young or old male speci- 

 mens of a swelling on the Mullerian duct (figured by Redeke), in 

 the region of the shell-gland of the female. 



Young Male Chimera monstrosa. 



The urogenital organs described below belonged to an animal 

 measuring : — 



From snout to end of whip-like tail 30 inches. 



From snout to anal opening 8 ,, 



Genital Organs. 



The frontal clasper is indicated, but not yet free, on the head, 

 and no spikes are yet in evidence. The middle claspers, in pouches 

 in front of the pelvic fins, are supported by cartilage, but are with- 

 out visible spikes, and only partially developed. The posterior 

 claspers are already well-marked, and subdivided into two main 

 portions, but the surface is still smooth. 



