Dr. G. Meissner on the Genus Mermis. 427 



females was remarkably wide — our author having found only 

 three males among several hundred specimens examined. He 

 divides the internal organs into testis, vas deferens, vesicula semi- 

 nalis, and ductus ejaculatorius ; but these are all continuous, 

 forming a cascal tube stretching from the anterior portion of the 

 body to the caudal extremity. The testis consists of the infun- 

 dibuliform csecal extremity of this tube and is lined with nucle- 

 ated, epithelial (?) cells. 



The external organs consist of two penises situated one on 

 each side of the ductus ejaculatorius in a sheath. They are 

 composed of two somewhat curved half-canals disconnected when 

 unprotruded with the internal organs ; but when protracted, they 

 form a more or less closed tube projecting beyond the external 

 orifice of the duct. 



Females. — Meissner divides the internal female organs, which 

 are double, into five portions : ovary, vitellus-organ, albumen- 

 sac, tuba, and uterus. Their names indicate their respective 

 functions, and we can here enter into no description of their 

 intimate structure. 



In connection with this should be noticed one point not a little 

 remarkable, that is, a kind of hermaphroditism occurring in 

 these animals. 



Meissner found individuals which had perfectly well-formed 

 internal female genital organs, but whose caudal extremity was 

 wholly male. Thus, there were the penises, with their protractor 

 and retractor muscles, their sheaths — in fact, all the external or- 

 gans of the male, yet iu these individuals no trace of internal 

 male or of external female organs could be found. Moreover 

 these organs present precisely the same characteristics as though 

 in proper males and females, and had also a functional activity, — 

 eggs being found in the ovaries, &c. But this anomaly was 

 never found in the inverse sense, that is, female external and male 

 internal organs. Here then is presented the striking peculiarity 

 of an animal having double systematically-developed internal 

 organs of one sex, and at the same time perfectly-formed external 

 organs of the other sex. This hermaphroditism, it will be seen, 

 is like that of other animals only in name; for in these last the 

 double sex is at the expense of the symmetry, one side being 

 female and the other male, or it is due to modifications of analo- 

 gous facts by different grades of development, thereby destroying 

 generally the functional perfection and completeness of each or 

 one of the forms of the sexual organs. But here we have a per- 

 fectly symmetrical female internally, with an equally symmetrical 

 male externally, with no fusion of parts. 



In regard to the development of the spermatic particles, our 

 author's researches have been minute and quite complete. His 



