Genito-urinary Apparatus of the Male Porpoise. 129 



departure from the usual mammalian configuration pre- 

 sented by Cetacea, yet in all the essential anatomical 

 features, not only the general regions but also the special 

 structures do not differ very materially from the conditions 

 which they display in other mammals. In view of the 

 entire disappearance of their hind pair of limbs, it is 

 interesting to note that on each side a fragment of the 

 innominate bone is preserved, the so-called pelvic bone. 

 No doubt this has remained owing to the vital importance 

 of the genital organs, and the necessity for providing the 

 external pudenda with an osseous basis of support. Con- 

 sidered from this point of view, it does not appear excessively 

 speculative to suggest that each pelvic bone represents one 

 half of the pubic arch of other mammals, and that, as in 

 them, the front part may be regarded as a pubic element, 

 while the hinder part is more particularly the ischial 

 element. 



Literature. — An admirable summary of literature is 

 appended to the work of Daudt above frequently referred 

 to, and where necessary we have referred to these memoirs. 



Description of Figures.: 

 Plate II. 



Fig. 1. External generative organs. 



Fig. 2. Diagrammatic transverse section throngh tlie trunk at the level of 



the testes. 

 Fig. 3. Diagrammatic transverse section through the trunk at the level of 



the kidneys. 

 Fig. 4. Diagrammatic transverse section through the trunk below kidneys. 



Figs, 2, 3, and 4 show the arrangement of the peritoneum. 



