]^74 S. GOTO. 



sion. If all the sets of muscular fibres of the body contract at the 

 same time, the investing membrane must be subjected to pressure from 

 within, great enough to evaginate the genital atrium and protrude the 

 penis. 



6. Eemarh on the Terminology of the Genital Organs — In conse- 

 quence of the complicated relation of the genital organs of the 

 Trematodes the same word has, on the one hand, been often used in 

 different , senses by diflferent writers, and on the other hand, cor- 

 responding organs have been designated by different names. It may 

 therefore not be quite out of place here to compare, without aim- 

 ing at exhaustiveness, the terms which have been used ''; confin- 

 ing our attention mainly to the ectoparasitic Trematodes. In his 

 " Saggio " Monticelli used the term " ovidotto interno " for that 

 portion of the female efferent duct which lies between the ovary and 

 the ootyp ; the latter he called " utero " ; while the remaining por- 

 tion, i. e., the portion lying between the ootyp and the external 

 opening, he called " ovidotto esterno." In his recently published 

 " Primo' contributo," however, he uses these terms in other senses. 

 Leaving the "ovidotto interno " with the same sense, he now ap- 

 plies the term " utero " to that portion which lies beyond the shell- 

 glands and which " conserva lo stesso calibro," and " ovidotto 

 esterno" for " sua porzione terminale, dove si allarga ad imbuto molto 

 allungata." The term " ootypo " he uses in the sense given it in the 

 present paper. 



Wright and Macallum in their paper on Sphyranura apply 

 the term " uterus " to the ootyp, and use the latter term for that 



1). The descriptions of Vogt in his piper, "TJeber die Fortpflanznngsorgane' einiger 

 ectx)parasitischer mariner Trematxiden " (Zeitsch. i. wiss. Zool., Bd. 30, SuppL, 1878, p. 306-340) 

 are unfortunately so imcioinpl&te and obscurBtKat I cOuld not make niuch use of them. His 

 terminology wUl not therefore be considered here, lest I should misinterpret his observations. 



