5O HENRY H. LANE. 



The unique feature in the ovisac as well as in the epithelial 

 Covering of the stroma of Lucifuga and Stygicola is the presence 

 of capillaries in the lining epithelium (Fig. 8). So far as could 

 be determined this condition has never been observed in the ovary 

 of any other form. So numerous are these capillaries that they 

 attract attention at the first glance. The epithelium itself is often 

 reduced to extreme thinness, sometimes serving merely as a mem- 

 brane to contain the blood. 



VII. THE OVARY. 



The ovarian structure itself is highly vascular and much lobed. 

 There is a tendency in some instances for these lobes to be ar- 

 ranged in a bilaterally symmetrical pattern, when seen in cross- 

 section, though this is not equally evident in all ovaries or even 

 in all parts of the same ovary. The ovarian structures of the 

 different specimens examined, while presenting numerous points 

 in common, are yet characteristically different in every case. 



The ovisac of A had but recently contained young, to judge 

 from its extreme thinness ; the stroma was so large that it gave 

 promise of containing embryos. Instead of that condition, how- 

 ever, it was found that the large size was due to the mass of 

 stroma which is composed in part of highly vascular tissue. 

 Numerous blood vessels penetrate the stroma in all directions 

 while around the ova themselves there is a network of capillaries. 

 The greater portion of the stroma is split up into numerous 

 sinuses, many of which are larger than any of its blood vessels. 

 These are closely similar in appearance to the " lymph-spaces ): 

 described by Stuhlmann (op. cit., p. 19) for Zoarccs and no doubt 

 serve the same purpose (Fig. 7, /.5.). 



The ova of A are few in number, less than ten over 60 /J. in 

 diameter appearing in any cross-section. Five or six ova are of 

 quite large size, visible even to the naked eye, and measuring 

 from 300 to 800 11 in diameter. They have a large amount, 

 proportionately of yolk-substance. The smaller ova are about 

 50 to 60 IJL in diameter, and are of the usual appearance of 

 ova of that size. The cells of the stroma in this ovary are very 

 irregular in shape, indistinct in outline, and usually of inconsid- 

 erable size. The nuclei are round, oval, or elongated, appar- 



