256 DE. T. S. COBBOLD ON ENTOZOA. 



gracilis, but is now satisfied as to its identity with T. affinis of 

 Eudolphi. In reference to tte reprodvictive organs of the male 

 T. affinis, the following observations were communicated : — " The 

 everted part of the sheath of the penis measures about the ^9^^ 

 of an inch in length ; it is perfectly transparent, not always uniform 

 in breadth, biit covered throughout its entire extent with minute, 

 conical, sharply pointed spines, whose apices are directed back- 

 wards towards the body of the animal. The occasional absence 

 of uniformity in the diameter of the sheath seems to be a point 

 of some importance ; for, had not my examinations extended over 

 a considerable number of examples, I might have been led to the 

 belief that I had to deal with several distinct forms of Tricho- 

 cepTialus. At first, indeed, this conclusion seemed inevitable ; but 

 finding iatermediate conditions between perfect uniformity and 

 the presence of a large flask-shaped distention near the free ex- 

 tremity, I can only suppose the variations to be due to the degree 

 of protrusion at which the organ has arrived*." 



Eespecting the female organs Dr. Cobbold offers the following 

 comment : — " In regard to the organs of generation in the female, 

 Kiichenmeister states that there are no external appendages in 

 TricJiocephalus comparable to those known to exist in the allied 

 Triehosomata. So far, however, from this being the case, there is, 

 in the present species at least, a remarkably prominent and more 

 or less hourglass-shaped sheath, — this projecting vulva,if it may be 

 so termed, being obliquely truncated at the free end, where it is 

 also hollowed out (or, rather, inverted) to give origin to the centrally 

 enclosed vagina, whose orifice is somewhat constricted. The sur- 

 face of this appendage is supplied with small spines, precisely like 

 those in connexion with the penis-sheath of the male, — the spines 

 being also retroverted. This observation is confirmed by the state- 

 ment of Mayer, who has described their occurrence at the vaginal 

 orifice of Trichoceplialus dispar. Dr. Joseph Eberth, of Wiirz- 

 burg, in a recent number of Siebold and Kolliker's Zeitschriffc, 

 rather incautiously denies the assertions of Mayer (vol. ix. p. 

 385), Having discovered long conical processes within the vagina 

 of T. dispar totally unlike those described by Mayer and myself, 

 he has inferred that the structures in question are the same as those 

 seen by us. I translate and quote Dr. Eberth's own words : — 

 * According to Mayer, these are similar inform and size to the spines 



* These appearances Were illiist rated h\ figia-es, whidi will be given, together 

 witli the paper itself, in the next JS'iunber of the Journal. 



