GILMORE ET AL.: REPRODUCTION AND EMBRYO DEVELOPMENT OF SAND TIGER SHARKS 



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FIGURE 9.— Two views of an 18.5 mm Odontaspis taurus embryo (IRCZM 103134) taken from the right uterus of a 282.5 mm TL female cap- 

 tured 4 September 1970, showing damage by intrauterine attacks from larger embryo. 



Posthatch and Intrauterine 

 Cannibalistic Period 



(June-September; 60-334 mm) 



This period is characterized by hatching of the 

 largest encapsulated embryos, consumption of yolk- 

 sac yolk supplies, and active cannibalism by the 

 largest hatched embryo upon other intrauterine en- 

 capsulated or small hatched embryos until only one 

 embryo remains. These events occur simultaneously 

 in each uterus. From June to September this 

 developmental period overlaps the latter part of the 

 early gestation phases of other sibling embryos. 



Two hatched embryos, 62 and 63 mm, (Fig. 13) from 



each uterus of a late June sand tiger shark were 

 noticably more robust than five 27-46 mm embryos 

 still encapsulated in these uteri. However, there was 

 no evidence that the larger embryos had begun to 

 feed upon other egg capsules, encapsulated em- 

 bryos, or other free embryos. The 62 and 63 mm 

 specimens still possessed 5.5-6.0 mm diameter yolk 

 sacs and branchial filaments. 

 At about 100 mm, the embryo has consumed the 

 contents of the yolk sac and begins obtaining 

 nourishment through adelphophagy and oophagy. 

 Evidence of intrauterine cannibalism was found in 

 the uterus of a 271.5 cm female 0. taurus, caught 18 

 July 1976, which contained a large hatched embryo 

 (100 mm) that had attacked and badly damaged 



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