304 



APPENDICES. 



The Weberian organ, or the uterus masculinus, is well devel- 

 oped in the beaver. It is triangular in shape, flattened and thin 

 antero-posteriorly, and is connected by its edges with the vasa 

 deferentiae. It lies between the bladder and the vesiculge semi- 

 nales. Below it seems lost in the thin connective tissue. In the 

 upper part, where it is l^" in width, is a small cavity without 

 any outlet. The filaments which extend from the superior angles 

 lie upon the vasa deferentiae, and disappear at the bottom of the 

 testicles, being 6|" in length. Tlie significance of this structure, 

 so interesting to the philosophical anatomist, is but at present a 

 matter of speculation. Homologous with the uterus, the vesi- 

 cula prostatica, as it is sojnetimes called, like the mammas of the 

 male, suggests the idea of typical structures, or of organs of 

 original utility, but dwarfed in the progress of development. 



Brawn by \V. W. My. 



In Fig. 3, the genital organs of the female arc represented. The 

 parts being dissected from the'r connections, and laid on a flat 

 surface before the drawing was made, their natural relations are 

 somewhat altered. The oil sacs and castoreum sacs are discon- 

 nected. They are much larger than the other specimen, relatively 

 to the size of the animal. The cloaca is laid open, and the vaginal 

 orifice is higher than in the natural state ; this, and the urethral 



