86 Bashford Dean Kiemorial Volume 



equal numbers. Among 569 specimens of Bdellostoma burgeri caught by Dean (Table 

 III), there were J2 young 'males and 63 young females, 230 adult males and 204 adult 

 females. I observed that the two sexes are about evenly distributed in number in 

 BdeUostoina stouti. 



GROWTH OF THE FEMALE GENITAL ORGANS 

 OF BDELLOSTOMA BURGERI AND BDELLOSTOMA STOUTI 



Both Dean and I caught females showing all stages of development of ova from mere 

 dots in the free margin of the mesovarium to eggs which were almost ready to be deposited, 

 measuring as much as 29 mm. in length. Dean made nine drawings of dissected females to 

 illustrate various stages in the growth of the eggs; these drawings are shown in Figures 

 6 to 14, plates II, III, and IV. 



The youngest female illustrated is shown in Figure 6, plate II. The ovary in this 

 individual contains many eggs, closely packed together, all spherical in shape, varying 

 in si2,e from mere dots to eggs 0.8 mm. in diameter. In all the females the smallest eggs are 

 located in the outermost part of the ovary along its free margin; successively larger eggs 

 lie internal to these, i.e., nearer the attached border of the mesovarium, the largest being 

 the most internal in position. The eggs in the specimen shown in Figure 6, plate II, 

 are distributed fairly evenly along the entire length of the ovary from the gall bladder to 

 within a few miUimeters of the caudal end. 



A slightly older female is illustrated m Figure 7- The largest eggs in this specimen 

 are spherical, and measure about one millimeter in diameter. The mesovarium is a little 

 broader in this individual. Figure 8 illustrates an older female, in which the largest eggs, 

 still spherical in shape, are about 1.5 mm. m diameter. The mesovarium is broader and 

 somewhat more folded. With progressive development the mesovarium increases in 

 breadth and becomes more folded, reaching the maximum condition in both these respects 

 in those females which have the largest eggs. 



In the ovary of a slightly older female than the one shown in Figure 8, the largest 

 eggs are beginning to assume a spindle shape by tapering at each end (Figure 9). The eggs 

 elongate as they develop further, as illustrated in Figure 10, plate II. The largest eggs 

 in this individual measure from 4 to 7 miUimeters in length, and occupy a position in the 

 ovary internal to all the other eggs. The next smaller eggs are about 2 mm. long and lie 

 immediately external to the largest eggs. Ova of successive gradations of diminishing 

 sizes occupy successively external positions in the ovary, with the smallest, which are 

 mere dots, in the extreme external or free margin. 



The largest eggs in the next older specimen (Figure 11, plate III) measure from 7 to 

 10 mm. long. They have grown in circumference as well as in length, and now are so 

 heavy that they have stretched the mesovarium where they are attached, and hang down 



