MEMBRANES, OVARIES, AND OVIDUCTS OF SALMONOIDS. 



195 



As the ova approach maturity,' the left ovary is nearly or quite always the longer, 



and it extends, tapering, to the posterior end of the abdominal cavity (fig. 7 a). About 

 at the point where the mesovarium as a suspensory membrane ends and forms the 



d & 



Fig. 6. — Drawing by Mrs. Effie B. Decker from a specimen of Oncorhynckus kisutch, 36 inches long, from Ankon Slougfa. 

 Alaska, July 10. 191 7. collected by Emest P. Walker, salmon inspector. Dorsal view of the posterior end of the abdominal cavity. 

 the abdominal wall somewhat spread out. In natural position this portion of the abdominal cavity is very narrow, and the 

 walls closely approximate. The intestine is laterally flattened and compressed so that it does not show beyond the edges of the 

 superimposed membrane, and the edges of the membrane are turned upward, forming a trough, a. Left ovary; b. right ovary; 

 c, upper severed edge of mesovarium; d. outer edge of ovarian membranous covering; e. fold or free border of the posterior exten- 

 sion of ovarian membrane, which joins with the other on median line of intestine forming an oviducal channel or trough; 

 /. oviducal channel, combination of e from both sides; p, lateral deflection and junction of oviducal membrane with abdominal 

 wall; k. genital pore; g, intestine; /, severed dorsal intestinal mesentery; w, posterior end of severed mesentery. 



beginning of the trough mentioned (f\g. 7 w), the posterior extension of the ovary 

 has no membranous attachment to the trough, but has a free fold or flap of mesovarial 

 or ovarian membrane along its upper itmer side which narrows posteriorly to the end 



* As observed in one specimen each of Atlantic and humpback salmon. 



