260 REPORT — 1851. 



sexual orifices and the testicular or ovarian masses been satisfactorily traced ; 

 so that Sir Everard Home was induced to believe that in the kind of inter- 

 course above alluded to, there was no transmission of impref!;nating fluid from 

 one animal to another, but that the excitement produced by mutual contact 

 caused both the ovaria and the testes to burst*, so tliat the ovaria escaping into 

 the cells of the body become there mingled with the spermatic secretion, and 

 being thus fertilized, the ova were hatciied internally, and the young, having 

 been retained for some time in the cells between the intestine and the skin, 

 Avere ultimately ejected through apertures which were supposed to exist in 

 the vicinity of the tail. 



" There is however little doubt that what SirE. Home conceived to be young 

 earth-worms were parasitic Entozoa, and that in the mode of their propaga- 

 tion, the animals we are describing exhibit but little deviation from what we 

 have alread}' seen in the Leech. 



"According to M.Duges the testes are placed in successive segments of the 

 body, from the seventh backwards ; they vary in number in different indivi- 

 duals from two to seven ; but whether this variety depends upon a difference 

 of species, or is only caused by the posterior pairs becoming atrophied when 

 not in use, is undetermined. Each testis is fixed to the bottom of the ring, 

 in which it is placed by a short tubular pedicle, that opens externally by a 

 very minute pore through which a milky fluid can be squeezed. The testi- 

 cular vesicles of the same side of the body all communicate by a common 

 canal, and the seminal fluid, which, like the seminal secretion of other ani- 

 mals, contains animalcules, can readily be made to pass from one to the 

 other. 



" The ovaria are eight large white masses of a glandular texture, from which 

 arise two delicate tubes or oviducts ; these have no connexion with the testes, 

 but running backwards, they become dilated into two small vesicles at their 

 termination, and open by two apertures or mdvce seen externally upon the 

 sixteenth segment of the body ; in these ducts eggs have been detected as large 

 as pins' heads! The eggs are laid when two or three lines in length. In 

 fig. 85, Af , one of them, enclosing a mature embryo, is delineated ; its top is 

 seen to be closed by a peculiar valve-like structure adapted to facilitate the 

 escape of the worm, and opening (fig. 85, B) to permit its egress. Another 

 remarkable circumstance observable in these eggs is, that they very generally 

 contain double yolks, and consequently two germs, so that a couple of young 

 ones is generally produced from each." 



By another distinguished systematic writer the following account is given 

 with reference to the mechanism of reproduction in the Earth-worm : — " In 

 the Earth-worm, towards the end of the summer, there is developed around 

 the body a thick and broad belt ; this is an apparatus for suction, by which 

 the worms are held together during congress. It is remarkable that the ova 

 do not escape through the ducts which serve to convey the spermatic fluid to 

 the ovaria; but the ovaria hurst when distended with mature ova, and allow 

 their contents to be dispersed through the interior of the animal. In this 

 respect the process of reproduction in the Earth-worm bears a striking ana- 

 logy to that which we have witnessed in the flowering plants ; for in the latter 

 the fertilizing influence is transmitted down the minute canals of the style, 

 and the seeds escape when ripe by the dehiscence of the walls of their enve- 

 lope. The ova of the Earth-worm pass backwards between the integument 

 and intestine to the anal extremity ; and in their progress they gradually 

 undergo their development and are expelled from their parent, either as com- 

 * The italics are mine. 

 t At p. 909 of the Aiiimal Kingdom, by Mr. Rymer Jones. 



