BULLETIN OF TIIE UNITED STATES FISII COMMISSION. 20D 



pass off from the dorsal and ventral somatic arteries, which tend to 

 branch into vessels of a capillary fineness amongst the productive folli- 

 cles. Thus the glandular portions of the reproductive organs are effect- 

 ively nourished by supplies of blood passing from the great vessels 

 given off by the heart. These are the principal characteristic features 

 of the reproductive follicles in the hermaphroditic and unisexual forms 

 which are noticed upon comparing the two together. The most impor- 

 tant differences between the two forms are to be found, however, in the 

 mode in which the generative elements are produced in each type, which 

 we will now consider. 



In 0. ediilis the reproductive glands when well developed show in 

 many cases a lining of large nearly mature ovules or ovarian eggs, at 

 intervals, and insinuated between them large coarsely granular bodies 

 may be observed, in which large, irregular, nuclear bodies are often 

 embedded. These nuclear bodies are further distinguished from those 

 of the ovules by their oval or oblong and often irregular form, and by 

 containing a dense mass of granules which absorb safranin in such 

 quantity as to become opaque. This granular chromatin, as it would 

 be designated by Flernining, is usually aggregated at the center of the 

 nuclear or cellular mass, whichever it may be, and is furthermore apt to 

 conform to a certain extent to the external outline of the body which 

 contains it. From these bodies the rounded granular cells appear to 

 arise, which fall into the cavity of the tubule or follicle, there to un- 

 dergo further segmentation, and finally break up into spermatozoa with 

 spherical heads and filiform tails or flagella. Even in some cases, where 

 no spermatozoa are as yet revealed by the methyl green, these rounded 

 spermogens or spermatoblasts are to be seen free in the center of the 

 follicles. Usually, however, the spermatoblasts have been crowded 

 towards the external end of the tubule where they have undergone dif- 

 ferentiation into spermatozoa. The spermatozoa are often on this ac- 

 count so crowded together at the outlet of the tubules, passing even 

 into the superficial ducts, so that when acted upon by the methyl 

 green they are revealed as a dense, almost opaque, dark, bluish-green 

 mass. The ovules, on the other hand, which may be quite nearly ma- 

 ture, remain unstained, except their spherical clear nucleus and nucleolus, 

 which is double, as if formed of two conjoined spherules. If the sa- 

 franin has been washed out of the nucleus the one spherule of the nucle- 

 olus only is apt to retain the color. The peculiar nucleus of the ovules 

 at once distinguishes them from the elements, which later break up and 

 become the spermatozoa. Apparently every phase of the spermatoge- 

 netic process is under way in the follicles, while more or less nearly 

 mature ovules may be adherent to the walls of the same tubules. In 

 some specimens I find the tubules to contain nothing but ova, with little 

 or no trace of spermatoblasts; in others, again, both classes of prod- 

 ucts may be present in about the same condition of maturity. In still 

 others little else but spermatozoa are to be found, but, adherent to the 

 Bull. U. S. F. 0., 82 U March 14, 1883. 



