206 BLIND VERTEBRATES AND THEIR EYES. 



115 mm. from Alacranes and Cafias, in all of which the ovary was empty and in 

 most cases at its minimum. 



In December all the ovaries but two were minute. In one ovary a single large 

 egg 720 ft was found, in the other the ovary was large and the eggs reached a 

 maximum of 640 p. Thus, nearly mature eggs were found in December and 

 March, and young in September and October. 



If the species breed annually and irregularly throughout the year and the 

 young are carried but 3 months, at least one-fourth of all the females caught at any 

 season of the year should be with young. If the young are carried but 2 months, 

 one-sixth of all the females should be with young. If the species breed at some 

 definite season of the year and this period is not more than 3 months long, all of 

 the females should be with young near the middle of the breeding season. 



The results are wide of any of these marks ; and the only conclusion possible 

 is that either there is no definite breeding season, but individuals breed at any 

 time during the year, or the fishes breed only at longer intervals than a year, and 

 in either case while breeding they migrate to undetermined regions. That these 

 regions are not far away is shown by the fact that occasionally breeding females 

 reach the upper accessible parts of the cave. Between breeding times they are 

 found in the upper, readily accessible parts of the cave. 



I found that while Amblyopsis probably breeds throughout the year a larger 

 per cent breed in March than in other seasons. A similar condition may exist in 

 the Cuban blind fishes. 



THE OVARIES OF STYGICOLA AND LUCIFUGA. 



The minute structure of the ovary of Lucifuga is elsewhere described. The 

 ovary consists of a pair of delicate walled sacks united behind and with the ovif- 

 erous tissues attached along the middle of its dorsal and ventral wall except for 

 a short distance behind. It is placed in the mesentery between the dorsal wall 

 of the body cavity and the rectum and stomach. In enlarged ovaries the oviferous 

 tissue is seen to be lobulated, the lobules being attached anteriorly and free pos- 

 teriorly. These lobules are arranged like shingles, the anterior ones overlapping 

 the posterior ones. When the ovaries contain no larvae or ripe eggs, they extend 

 far forward, the posterior oviferous tissues reaching but little behind the stomach. 

 When eggs mature, the ovary becomes turgid and the oviduct apparently shortens, 

 so that the posterior part of the stomach comes to lie in the fork near the anterior 

 end of the ovary. 



The spermatozoa are evidently, as in Cymatogaster, which is another vivi- 

 parous fish, transferred to the female long before the eggs are mature. When 

 mature the eggs are probably 850 /a in diameter, or even larger. Spermatozoa 

 were found in an ovary containing eggs but 560 /a in diameter. 



The number of young found in Lucifuga were 4, 15, and 10 respectively. The 

 young were nearly all turned with their heads toward the front of the ovary, a 

 condition duplicated in the ovary of Cymatogaster with nearly mature young. The 

 condition of the young in the ovary with 4 young is well shown by the photograph 

 (plate 15, fig. c). There were 2 young on each side. The largest eggs in this 

 ovary were 200 [t. in diameter. 



