226 BLIND VERTEBRATES AND THEIR EYES. 



ON THE OVARY AND OVA IN LUCIFUGA AND STYGICOLA. 

 (By Henry H. Lane.) 



In the Biological Bulletin, vol. 6, No. i, December, 1903, the ovarian 

 structures of Cuban cave fishes, Lucifuga and Stygicola, were described as 

 minutely as the few specimens then at hand would allow. A much larger series 

 of the ovaries of these fishes has since been put at my disposal. A study of these 

 44 ovaries (21 of Lucifuga and 23 of Stygicola) enables me to correct some minor 

 errors and to make some observations additional to those already recorded, and these 

 are submitted as follows : 



A few terms may be defined for the sake of clearness. These are : 



oviduct: the unpaired duct leading from the ovary to the urogenital pore. 

 It is not in Teleosts generally the homologue of the Miillerian duct of 

 other vertebrates. 

 ovisac: the anterior enlargement and continuation of the oviduct, covering 



the ovary proper. 

 ovary: the organ containing the ova. It is, however, sometimes convenient 

 to speak of the ovisac and ovary proper together simply as the "ovary." 

 In such cases the context prevents ambiguity. 

 stroma: the tissues of the ovary proper other than the ova and their follicular 

 membranes. 



GROSS STRUCTURE. 



Externally the ovaryis a Y-shaped, subcylindrical organ (plate 27) with a bilateral 

 arrangement of the stroma. Its greatest diameter is usually immediately posterior 

 to the point where the two horns begin. These horns of the ovary are right and left 

 in position and may be long enough to inclose between them the posterior part of 

 the stomach, though there is much variation in their length (plate 27). Within the 

 ovisac the stem of the Y is divided by a median partition with which the ovarian 

 structures proper are associated, in some ovaries more distinct than in others. This 

 median sagittal partition extends posteriorly to the region I have chosen to consider 

 the beginning of the oviduct, where in most cases only the part attached to the 

 ventral wall persists ; in others the part attached to the dorsal wall is also present, 

 though separated from the ventral part by a fissure. From the tips of the ovarian 

 horns slender but comparatively strong threads of connective tissue, inclosing 

 blood-vessels, run cephalad and fasten to the peritoneal walls, thus assisting in 

 securely holding the ovary in position. Dorsally, a mesovarium suspends the organ 

 from the peritoneal lining of the body cavity, while ventrally there is a correspond- 

 ing attachment, the mesorectum. Each horn of the ovary is supported by its own 

 fold of peritoneum and these two become united at or near the point of division of 

 the horns and are continued posteriorly as the single, thicker mesovarium sup- 

 porting the body of the ovary and the oviduct. The mesorectum is not always 

 complete in the region of the ovarian horns. 



The oviduct, which has its external orifice at the urogenital pore, increases 

 gradually in size as it extends forward toward the ovary and finally becomes the 

 ovisac surrounding the ovary proper. 



