UROGENITAL ORGANS 



361 



a groove on the edge of each ovary, while in other groups the edges of the 

 groove unite so that a hollow gonad is formed. The eggs ripen and escape into 

 this cavity when it is present; in the others they escape into the coelom. 



The ovarian ducts are not homologous. In most salmonids and scattered 

 species from other groups the eggs pass from the coelom to the exterior through 



Fig. 381. — Schematic representation of the enclosure of the teleost ovary by the 

 ccBlom, in surface view and sections, after Haller. /, peritoneal fold; 0, ovary; d, 

 terminal duct; V, ventral side of sections. 



sex openings which may be modified abdominal pores (p. 19) behind the anus. 

 These are sometimes extended inside the coelom by a short funnel (fig. 382). 

 In all other cases there is a direct extension of the saccular ovary into a shoit 

 jviduct like that of Lepidosteus, with an opening on either side behind the anus. 



•'^wBB^S^^^W^^^^^^^^tffi^^- 



Fig. 382. — Relations of oviducts and pori abdominales in Coregonui,'' alter ^Veber. 

 a, anus; i, intestine; n, nephridial opening; 0, ovary; p, pore of right side; r, opening of 

 oviduct. 



In most teleosts the number of eggs produced in a season is very large, some- 

 times numbering millions. Usually, after passing from the oviducts they arc 

 left to the mercy of the water, but a number of species (Embiotocids, several 

 Cyprinodonts,(7aw6«5x<i) are viviparous, the eggs developing in the hollow ovary 

 or its ducts, which in some cases provide nourishment for the growing young. 

 In these fish there must be internal fertilization, but copulatory organs are 



