J 



548 



Bashjord Dean Memorial Volume 



IMMATURE OVARIAN EGGS 



Among the frilled-shark material loaned by the Department of Zoology of Columbia 

 University are five ovarian eggs of different sizes. No. 1 (42 x 34 x 34 mm.) is greatly 

 flattened on one side and is devoid of follicular membranes. No. 2 (45 x 38 x 38 mm.) 

 is shaped like a hen's egg and is surrounded with fragments of the follicular membranes. 

 No. 3 (46 X 46 X 35 mm.) is without follicular membranes. No. 4 (58 x 50 x 44 mm.) is 



enclosed in follicular mem- 

 branes. No. 5 — also enclosed 

 in follicular membranes — 

 measures 60 x 49 x 49 mm. 

 These are all immature eggs, 

 probably about half-grown. 



Other sizable (and in this 

 case larger) ovarian eggs are 

 those noted and sketched by 

 Dean and taken from his huge" 

 1960-mm.sharkcaptured April 

 27. Of the 16 eggs in question 

 in the two ovaries, 14 measur- 

 ed 70 x 30 mm. and 2 were 

 60 X 30 mm. They approached 

 maturity much more than the 

 smaller eggs just listed above. 

 Last of all are the huge ovarian 

 eggs reported by Momose 

 (1938) fromhisl510-mm. speci- 

 men taken November 28. 

 These, measuring 80-83 mm. 

 in diameter (Text-figures 3 

 and 9), were almost mature as 

 will be seen from the data in 

 the following paragraphs. 



Text-figure 12 

 A ripe ovarian egg in its ovarian and follicular membranes. The 

 circular area on top is probably a thin place in the membranes where 

 the follicle will rupture to set the egg free into the coelom. This is 

 probably the same egg as that shown in Figure 1, plate I. It is 

 presumably figured in natural sizie. 



Photograph by Bashford Dean. 



A MATURE OVARIAN EGG 



Such an egg is shown in Figure 1, plate I. In the original drawing, it measures 

 90 X 96 mm., and it was presumably drawn in natural size. It is of approximately the 

 same size as the eggs in round capsules shown in plate I. Its measurements are close to 

 those of eggs with gastrulae or very young embryos described by Nishikawa and by Dean 

 as found in the uteri. 



This egg (Figure 1, plate I) is enclosed in the egg follicle and is covered by the thin 

 peripheral membranes of the ovary. These membranes are folded into ridges shown as 



