102 MR. NEWPORT ON THE ORGANS OF REPRODUCTION, 



seems reason to believe, as we shall presently find that the ova in ttie female are 

 secreted in sacs which appear to be analogous to these caeca in the male organs. 

 I am inclined to think that the spermatozoa are not developed until the granulous 

 fluid has passed into the efFerential ducts at the season of impregnation. 



In the female the organs of reproduction (fig. 4.) are as simple as those of the male. 

 They consist of a single elongated bag, or oviduct, covered on its exterior surface 

 with a very great number of ovisacs or caeca, of various sizes, each of which secretes 

 but a single ovum. This oviduct extends backwards beneath the alimentary canal 

 from its double vaginal outlet {a a) in the fourth segment behind the second pair of 

 legs, as far as the posterior part. of the rectum, close to the anus, where it ends in a 

 cul de sac {d). It is most nearly in contact with the alimentary canal on its upper 

 surface, but is separated from it by adipose tissue ; in the pregnant female it is 

 smooth and distended with ova, that have passed into it from the ovisacs, and are 

 ready to be deposited immediately after intercourse with the male. The ova at the 

 anal extremity of the duct are as perfect as those near the vaginal outlets. The 

 oviduct contains in its cavity at least from seventy to eighty of these perfect eggs, 

 awaiting impregnation, arranged in two or more irregular rows, and greatly dis- 

 tending its sides. In some of the larger species of the genus there are four, and 

 in others five rows of eggs, the number of which is much greater than in our native 

 species. Treviranus* merely described the ovary as formed of two rows of eggs, 

 but the proper ovaries or ovisacs entirely escaped his observation. The ovisacs are 

 distributed thickly, to the number of many hundreds, over the whole exterior of 

 the oviduct (fig. 4 and 5. c c), from its posterior or ceecal extremity to within a short 

 distance of its vaginal outlets. Each ovisac, whatever be its state of development, 

 contains but a single ovum, every part of which is produced in it, from the germinal 

 vesicle, in the most rudimentary form, to the yelk, albuminous fluid and shell. This 

 fact deserves particular consideration. A large proportion of the ova in their ovisacs 

 never arrive at maturity, but are retarded in their growth by the more rapid develop- 

 ment of others that are near them ; so that on examining an oviduct partially dis- 

 tended with ova, the greater number of ovisacs, in different states of development, 

 are at the sides, and on the under surface of the duct, in parts which correspond to 

 the interstices between the fully developed eggs that have passed into the oviduct, or 

 are still forming on its exterior. One row of ovisacs usually exists on each side of the 

 duct, near its upper part, but most of the ovisacs in the course of development are at 

 its sides. The structure of the duct, and of the numerous ovisacs, is best seen in 

 those specimens which have not yet arrived at maturity, or in those which have just 

 deposited one laying of eggs. In these individuals the oviduct (5, c), to within a short 

 distance of its division into two outlets, is studded with minute ovisacs, each filled 

 with the rudiments of its minute ovum. Its general appearance in a female that has 

 recently deposited its eggs, is completely botruoidal (fig. 5.), very like the ovary of 



* Loc. cit. 



