MORPHOLOGY OF HIGHER TYPES 



129 



into the coelomic cavity and are collected in the ovisacs, where they 

 remain until they finally pass down the oviducts to the exterior. The two 

 pairs of receptacula seniinis are sac-like organs in which sperms arc 

 received at copulation and stored for future use in fertilizing the ova. 

 They are located anterior to the male organs and have no ducts communi- 

 cating with the other parts of the female reproductive system. 



Highly Complex Reproductive Systems in Invertebrates. — In many 

 species the ova are fertilized internally. In such animals there are 

 special organs for the delivery of the spermatozoa by the male, and for their 



i/.e 



Fig. 96. — Proglottis of a tapeworm, Protoocephalus, diagrammatically representing 

 reproductive organs, fp, fertilization passage; oot, ootype; ov, ovary; ovd, oviduct; p, 

 penis; pp, penial pouch; rs, receptaculum seminis; ts, testis; ut, uterus; va, vagina; vd, 

 vas deferens; ve, vasa efferentia; vg, vitelline gland: vgd, duct of vitelline gland; vr, vitelline 

 reservoir. 



reception by the female. There is usually an organ or organs for the 

 storage of eggs before and after fertilization. In this organ, the uterus, 

 the young may develop. Other special organs may also be present. 

 The genital system of Proteocephalus, a genus of tapeworms, may be used 

 to illustrate the arrangement of these organs in the complex systems of 

 some of the lower invertebrates ( Fig. 96). These worms, like the earth- 

 worm, possess both male and female systems in the same animal. The 

 male organs consist of many testes which are connected to a coiled tube, 

 the vas deferens, by means of minute an? stomosing tubules the vasa effer- 

 y 



