Table 2.

Average measurements (in mm) of the scleral cup of the three modern shark species (spiny dogfish, Squalus acanthias; blue shark, Prionace glauca; porbeagle, Lamna nasus) (n = 2 for each species). D, L, W, a and b are shown in Fig. 2. Fork lengths as an indicator of body length are given in cm for each of the two specimens

	Spiny dogfish shark	Blue shark	Porbeagle shark
Depth (D)	18.2 ± 0.4	43.8 ± 4.2	34.8 ± 1.4
Length (L) × Width (W)	27.8 ± 1.1 × 23.1 ± 0.4	64.4 ± 0.4 × 62.8 ± 2.6	55.6 ± 0.3 × 52.0 ± 0.3
Aperture (a × b)	20.1 ± 0.6 × 13.6 ± 1.2	30.2 ± 3.6 × 26.0 ± 1.8	34.3 ± 0.7 × 30.0 ± 1.0
Body length	68–74	175–179	158–179