St. Andrews Marine Laboratory . 481 



A careful watch had been kept on the species throughout 

 the spring ; but it was not till the 12th of June that Mr. 

 Prince, in my absence, procured a female with the ovaries so 

 advanced as to give reliable data with regard to the eggs. 

 Other females in a more or less developed condition were pro- 

 cured in July. In these the total bulk of the ovaries is by no 

 means noteworthy, even at the breeding-season. They form 

 a somewhat cordate mass, bifid in front, but connate poste- 

 riorly, and, like the spermaries, have a coating of the silvery 

 peritoneal lining on the surface. Some of the ova were trans- 

 parent, and thus, though small ('025 to "03 inch in diameter), 

 appeared to be mature. In their very early condition in 

 the stroma of the ovaries these ova present a characteristic 

 appearance (PL XIII. fig. 3), for shortly after passing 

 from the stage of a mere nucleated cell the Q,^g appears to have 

 a double capsule (PI. XIII. fig. 4), viz. an inner clear coat 

 probably homologous with the zona radiata of other Teleos- 

 teans, and an outer one of beautifully-arranged hexagonal 

 cells. The two divisions just mentioned, however, belong 

 to one layer, as shown in sections made by Mr. Prince. 



About a week later (8th August) a female with more fully- 

 developed eggs was procured ; indeed, the specimen seemed 

 to have deposited part of its ova, some of which lay externally 

 around the reproductive aperture. From the pellucid appear- 

 ance of the eggs in various specimens it formerly appeared 

 probable that they were pelagic, and the condition in this 

 example cleared' up any doubts. The translucent ova are 

 very small, nearly approaching those of the common dab in 

 this respect, and thus a very large number are held even by 

 the small ovaries. When mature each ovum (PI. XIII. fig. 1) 

 has a very fine hyaline zona radiata^ with a series for the 

 most part of hexagonal reticulations like those of a honey- 

 comb. These spaces are not quite uniform in size, but 

 many are. Some again have four, six, and seven sides. 

 When the edge of the sphere is examined the septa bound- 

 ing the reticulations stand out very distinctly, and their 

 edges show minute stri^ (PI. XIII. fig. 2). In transverse 

 section of the partially developed Q,gg in the ovary (PI. XIII. 

 fig. 4) the thickness of the zona radiata is in marked contrast 

 with that in the fully mature ova. The external reticulations 

 are imperfectly seen in preparations, as they form a confused 

 layer from collapse. The exact function of this arrangement is 

 unknown, but it enables the ^^^^ to be distinguished at once 

 amongst its congeners. 



So far as observed, a considerable number of ova, propor- 

 Ann. & Mag, N. Hist. Ser. 5. Vol. xvi. 33 



