94 Animal Morphology. 



expending it where it is required at least, such is the 

 notion here advocated. 



With this preliminary explanation, an attempt will be 

 made to describe its morphologies, and transpositions, and 

 displacements. 



It will be observed that the genito-uririary membrane, in 

 its true morphology, is so far free from contiguity in its 

 membranes, that it really has no serous membrane until 

 the independent sexes are made one by cpnception. 



Again, in the mammary membrane displacement is 

 recognised in its fullest sense, and displacement is used to 

 economise membrane in its completest form. 



Moreover, it is doubtful whether the mammary membrane 

 is not extended in the sexes to the erectile tissues, not only 

 of the nipples, but also to the clitoris and the corpus 

 spongiosum and cavernosum, as highly-modified serous 

 membrane ; and the mucous membrane of the glans as 

 modified mucous membrane, ending at the commence- 

 ment of the urethra, the muscular membrane being repre- 

 sented by the accelerator urinse and erector penis ; the 

 excess of the mammary membrane in the teats, as an 

 erectile tissue of the female, being compensated by the 

 excess in the male organ of generation by the highly- 

 modified serous membrane, as corpus spongiosum and 

 cavernosum. 



If, then, displacement of membrane in the several parts 

 of a tripartite membrane is admitted in the genito-urinary 

 and mammary membranes, it is equally applicable to the 

 ganglionic tripartite membrane. 



It is probably the fact that the lacteo-lymphatic membrane 

 and the ganglionic tripartite membrane are complimentary 

 membranes, and where one is absent the other is also, and 

 they are both supplementary to the circulatory or the veno- 

 arterial membrane, and are tributary and subservient to it. 



