TmOHOCEPHALUS. 



77 



I"iGS. 16 and 17. — Caudal extremity of Trichocephalns affinis. Outlined, -witli the aid of a camera, 

 from two separate specimens mounted and preserved in glycerine, a, epidermis ; J, cutis ; o, 

 coecal end of testis : d, seminal duct ; e, intestine ; f, muscle surrounding the sheath of the 

 penis ; g, sheatlt, and g, its infundibuliform base ; g, inner boundary of the sheath ; g, flask 

 or cup-shaped extremity of the sheath ; A, transverse rings ; i, spieulum ; i, base of the spicule, 

 and i, its free curved extremity ; Tc, mass of spermatic particles ; I, cloacal cavity ; m, anus. — 

 Original. 



