FISHERY BULLETIN: VOL. 81, NO. 2 



the uterus which is heavily folded and vascularized 

 near its opening. The 7-8 mm uterine wall in 0. taurus 

 does not function in placentation as in carcharhinid 

 sharks. The paired uteri unite posteriorly to form a 

 common vagina. 



Ovarian Activity 



This period begins from January to April with in- 

 semination of the female 0. taurus and extends into 

 the following September as exhibited by the pro- 

 longed fertilization of ova via stored sperm. Ova fer- 

 tilization apparently occurs in the anterior oviduct or 

 oviducal gland (Fig. 3Ba, b) prior to egg capsule for- 

 mation. The oviducal gland then produces a variety 

 of collagen egg capsules, some of which contain fer- 

 tilized ova (Figs. 4, 5). Egg capsules are then 

 deposited in the uterus. Although encapsulated em- 

 bryos are present in the uterus for 5-6 mo, the 

 development of a single embryo from fertilization to 

 hatching in utero takes about 3-4 mo. 



The number of ova and the general overall size of 

 the ovary increased during early pregnancy. During 

 this period, ova diameters ranged from 2.0 to 10.2 

 mm and weights ranged from 1.6 to 410 mg. A 254.5 

 cm TL female 0. taurus captured 15 May 1977 con- 

 tained a 4.6 kg ovary with 22,180 ova 1.3-10.0 mm in 

 diameter (Table 2). Encapsulated fertilized ova (i.e., 

 blastodiscs were evident) were present in the uterus, 

 but no embryos. All 11 sand tiger sharks examined 



between June and August possessed greatly hyper- 

 trophied right ovaries (left ovaries are atrophic and 

 nonfunctional) weighing between 3.7 and 8.5 kg and 

 taking up considerable space (360-455 mm in length) 

 in the body cavity (Fig. 3, Table 2). The largest ovary 

 (8.5 kg) came from an 8 July 1978 sand tiger shark, 

 which also had two embryos that were past the "ear- 

 ly" uterine developmental stages and in the "post- 

 hatch" cannibalistic stage during which consump- 

 tion of ova would be their primary means of 

 nutrition. 



Oviducal Gland Activity 



The paired oviducts of 0. taurus may be divided into 

 four basic sections (Fig. 3B). The anterior portion (a) 

 is a narrow tube lined with ciliated columnar epithe- 

 lial cells, extending between the ostium and the 

 oviducal or nidamental gland. This anterior tube is 

 310 mm long in a 254 cm sand tiger shark and about 9 

 mm in diameter. The oviducal gland (b) secretes 

 mucus, ovalbumin, and the major elasmobranch egg 

 case component, collagen (Wourms 1977). Neither 

 the anterior portion of the oviduct nor the oviducal 

 glands were sectioned and examined in detail for 

 sperm storage; therefore, the exact site of fertiliza- 

 tion in O. taurus remains unknown. However, fer- 

 tilization must occur prior to encapsulation of the ova 

 in the shell membrane or collagen egg capsule. En- 

 capsulation takes place within the oviducal gland. 



TABLE 2. — Comparative reproductive data for female Odontaspis tauruf 



capture, 1947-78. 



arranged chronologically by month of 



206 



