ENTOZOA. 



137 



by a small orifice in the centre of that part,* 

 and the corresponding cavities from which a 

 clear or milky fluid is ejected by the posterior 

 pores of some smaller species of Distomata 

 and Diplostomata.-\ 



Organs of generation. The generative sys- 

 tem in the Entozoa presents great varieties 

 in the form, structure, and combination of 

 its several parts. Sometimes the female or 

 productive organs alone are discernible. In 

 many Cestoidta, and in all the Trematoda, 

 the male gland is present and communicates 

 with the oviduct, so that each individual 

 is sufficient for itself in the reproductive 

 capacity. In the Acanthocephala and Ne- 

 matoidea the sexes are distinct, and a con- 

 currence of two individuals is required for 

 impregnation. 



No trace of a generative apparatus has hither- 

 to been detected in the Cystic Entozoa. They 

 would seem to be gemmiparous, and to have 

 the reproductive power diffused over the whole 

 cyst, at least in the Acephalocysts, in which 

 the young are not developed from any special 

 organ, or limited to any particular part of the 

 cyst. 



The ovaries in the most simple of the Ces- 

 toid worms, as the Ligula, are situated in the 

 centre of each joint, where they open by a 

 transverse aperture, from which projects a 

 small filamentary process or lemniscus, re- 

 garded by Rudolphi as a male organ. In the 

 Bothriocephali the ovaries have a similar po- 

 sition, and in the Bothriocephalus latus (Jig. 89) 

 assume a stellated figure, with 

 .F/g. 89. the aperture in the centre, 

 R tj which is situated in the mid- 



dle of each joint. In the 

 Bothriocephalus microcephalus 

 the ovary consists of one or 

 two rounded corpuscles in the 

 centre of the joints, but the 

 generative orifices are margi- 

 nal and irregularly alternate, 

 and the oviducts may be dis- 

 tinctly seen passing backwards 

 to them. 



In the T&nia Candelabra- 

 ria a sacciform ovary exists 

 in each segment, which sends 

 off an oviduct to the marginal 

 outlet. Besides which, ac- 

 cording to Rudolphi, there is 

 a longitudinal canal, uniting 

 Ovarian aperture* ^different ovaries together, 

 and ma, Bothrio- and undergoing a partial dila- 

 cephalus latus. tation at the anterior part of 

 each joint. May not this be 

 the male organ ? 



The androgynous structure of the generative 

 apparatus is very well displayed in the Tape- 

 worm of this country, the Tama Solium. 



In each joint of this worm there is a large 

 branched ovarium (i, Jig. 90) from which a 

 duct (h} is continued to the lateral open- 



* See Zool. Trans, pt. iv. vol. i. p. 381. pi. 41. 

 fig. 18. See Nordmann, loc. cit. p. 38. 

 t See Nordmann, loc. cit. p. 140. 



Fig. 90. 



Generative organs magnified, Taenia tolium. 



ing. The ova are crowded in the ovary ; 

 and in those situated in the posterior segments 

 of the body, they generally present a brownish 

 colour, which renders the form of their recep- 

 tacle sufficiently conspicuous.* In segments 

 which have been expelled separately, we have 

 observed the ovary to be nearly empty, and it 

 is in these that the male duct and gland is 

 most easily perceived. For this purpose it is 

 only necessary to place the segment between 

 two slips of glass, and view it by means of a 

 simple lens, magnifying from twenty to thirty 

 diameters: a well-defined line (g), more slender 

 and opake than the oviduct, may then be 

 traced extending from the termination of the 

 oviduct, at the lateral opening, to the middle 

 of the joint, and inclining in a curved or 



* The dendritic ovarian receptacles can also be 

 injected with mercury or coloured sizo, and they 

 have been regarded, but erroneously, as forming 

 part of the nutrient apparatus. 



