108 LECTURE VI. 



single, corresponding to the testis in the male, but in the greater 

 number of the nematoid worms it consists of two filamentary tubes. 



The Strongylus giyas is an example of the more simple structure 

 above alluded to.* The single ovary commences by an obtuse blind 

 extremity close to the anal extremity of the body, and is firmly 

 attached to the termination of the intestine; it passes first in a straight 

 line towards the anterior extremity of the body, and, when arrived 

 to within a short distance from the vulva, is again attached to the 

 parietes of the body, and makes a sudden turn backwards ; it then 

 forms two long loops about the middle of the body, and returns again 

 forwards, suddenly dilating into an uterus, which is three inches in 

 length, and from the anterior extremity of which a slender cylindrical 

 tube or vagina, about an inch in length, is continued, which, after 

 forming a small convolution, terminates in the vulva, at the distance 

 of two inches from the anterior extremity of the body. 



In the Trichocephalus dispar the ovarium and uterus are conti- 

 nuations of one and the same single tube, which by its folds more or 

 less conceals the intestines ; the vulva is situated nearly at the junction 

 of the filamentous with the thick part of the body. The female ge- 

 nerative tube is, also, single in TricJiosoma, in Sphcerularia, in 

 Filaria rigida, and in Ascaris paucipara. 



The theory which had suggested itself to Rudolphi, of the correla- 

 tion of a simple oviduct in the female with the spiculum simplex of 

 the male, and of the double oviduct with a spiculum duplex, is dis- 

 proved by the circumstance of the uteri and oviducts being double 

 in the Strongylus armatus and in the Ascaris lumbricoides, in the 

 males of which the penis is a single spiculum. In the Strongylus 

 injlexus, which infests the bronchial tubes and pulmonary vessels of 

 the porpoise, each of the two female tubular organs may be divided 

 into ovary, oviduct, and uterus ; the ovary is one inch in length, 

 commences by a point opposite the middle of the body, and, after 

 slightly enlarging, abruptly contracts into a capillary duct about two 

 lines in length, which may be termed the oviduct or Fallopian tube, 

 and this opens into a dilated moniliform uterus three inches in length. 

 Both tubes are remarkably short, presenting none of the convolutions 

 characteristic of the oviducts of Ascaris and Filaria, but extend in 

 a straight line (with the axception of the short-twisted capillary 

 communication between the ovai'ia and uteri) to the vulva, which 

 forms a slight projection below the curved anal extremity of the 

 body. The reason of this situation of the vulva seems to be the 

 fixed condition of the head of this species of Strongylus. In both 



* LX. p. 141. fig. 95. 



