SEXUAL GENERATION. 



541 



Fig. 175. 



whole is surrounded by a circle or crown of delicate and brilliantly 

 colored leaves, termed the corolla (d), which is frequently provided 

 with a smaller sheath of green leaves outside, called the calyx (e). 

 The anthers, when arrived at maturity, discharge a fine organic 

 dust, called the pollen, the granules of which are caught upon the 

 extremity of the pistil, and then penetrate downward through its 

 tissues, until they reach its lower extremity and come in contact 

 with the germ. The germ thus fecundated, the process of genera- 

 tion is accomplished. The pistil, anthers, and corolla wither and 

 fall off, while the germ increases rapidly in size, and changes in 

 form and texture, until it ripens into the mature fruit or seed. It 

 is then ready to be separated from the parent stem ; and, if placed 

 in the proper soil, will germinate and at last produce a new plant 

 similar to the old. 



In the above instance, the male and female organs are both 

 situated upon the same flower ; as in the lily, the violet, the con- 

 volvulus, &c. In other cases, there are separate male and female 

 flowers upon the same plant, of which the male flowers produce 

 only the pollen, the female, the 

 germ and fruit. In others still, 

 the male and female flowers are 

 situated upon different plants, 

 which otherwise resemble each 

 other, as in the willow, poplar, 

 and hemp. 



In animals, the female organs 

 of generation are called ovaries, 

 since it is in them that the egg, 

 or "ovum," is produced. The 

 male organs are the testicles, 

 which give origin to the fecun- 

 dating product, or "seminal 

 fluid," by which the egg is fer- 

 tilized. We have already men- 

 tioned above that in the articula- 

 tions of the tapeworm the ovaries 

 and testicles are developed to- 

 gether. (Fig. 175.) The ovary 

 (a, a, a) is a series of branching follicles terminating in rounded 

 extremities, and communicating with each other by a central canal. 

 The testicle (b) is a narrow, convoluted tube, very much folded 



SlXflLB A R T I C t r I. A T I O * OF 



CK ASS iroLMs, from small intestine of cat 

 n, a, a. Ovary filled with eggs. b. Testicle, c. 

 Genital orifice. 



