ii2 SHELVE DISTRICT 



Table 78 



Statistics of length (1) and length of adductor scars from umbo (sc) in n brachial valves of Tissintia 



prototypa (Williams) from the Weston Beds (A) and the Lower Llanvirn of Llandeilo (B), and of 



T. immatura (Williams) from the Meadowtown Beds (C) 



A B C 



n 12 6 34 



1 mm (var 1) 10-43(8-345) 11-18(3-402) 8-08(15-198) 



sc mm (var sc) 4-77 (1-599) 5-13 (0-926) 4-04(2-818) 



r 0-935 0-979 0-984 



a (var a) 0-4377 (0-00242) 0-5217 (0-0028) 0-4306 (0-00018) 



Table 79 



Statistics of length (1) and maximum width (w) of n brachial valves of Tissintia prototypa 



(Williams) from the Weston Beds (A) and the Lower Llanvirn of Llandeilo (B), and of 



T. immatura (Williams) from the Meadowtown Beds (C) 



ABC 



n 27 54 52 



1 mm (var 1) 6-92(18-479) 7-62(9-47) 5-66(11-628) 



w mm (var w) 9-01(29-887) 9-25(10-229) 7-11(15-49) 



r 0-987 0-903 0-99 



logel ( var log e l) 1-771(0-3265) 1-9559(0-1508) 1-5786(0-3097) 



log e w (var log e w) 2-0424(0-3131) 2-1678(0-1129) 1-8275(0-2674) 



r e 0-989 0-91 0-992 



a (var a) 0-9793 (0-00464) 0-8653 (0-00247) 0-9292 (0-00027) 



Table 80 



Statistics of length (1) and thickness (th) of n pedicle valves of Tissintia prototypa (Williams) from 

 the Weston Beds (A) and the Lower Llanvirn of Llandeilo (B), and of T. immatura (Williams) 



from the Meadowtown Beds (C) 



ABC 

 n 14 31 49 



1 mm (var 1) 10-81(18-219) 7 - 88 (3-719) 7-18(12-06) 



th mm (var th) 2-59 (1-299) I- 45 (° -I 7) 2-19 (0-925) 



r 0-895 0-800 0-932 



a (var a) 0-267 (0-00118) 0-2138 (0-00057) 0-277 (0-00022) 



Table 81 



Statistics of length (1) and length of dental plates (dl) in n pedicle valves of Tissintia prototypa 



(Williams) from the Weston Beds (A) and the Lower Llanvirn of Llandeilo (B) , and of T. immatura 



(Williams) from the Meadowtown Beds (C) 



ABC 



n 21 27 53 



1 mm (var 1) 11-45(9-102) 8-36(3-282) 6-92(14-129) 



dl mm (var dl) 1-68 (0-328) 1-06 (0-055) i'i8 (0-341) 



r 0-909 0-624 0946 



logel (var log e l) 2-4044(0-0671) 2-0999(0-0461) 1-8049(0-2586) 



logedl (var logedl) 0-4614(0-1103) 0-0297(0-0484) 0-0522(0-2205) 



r e 0-914 0-627 0-952 



a (var a) 1-2822 (0-0143) 1-0246 (0-02548) 0-9234 (0-00157) 



