ordovician brachiopoda 57 



Table 36 



Statistics of length of brachial valve (1) and length of brachiophores at their bases (c) for n 

 specimens of Orthambonites exopunctata sp. nov. (A) and of Lenorthis cf. proava (Salter) (B) 





A 



B 



n 



8 



13 



1 mm (var 1) 



6-i6 (4-389) 



5-6 (1-833) 



c mm (var c) 



1-19 (0-167) 



o-8 (0-032) 



r 



0-971 



0-729 



a (var a) 



0-195 (0-00036) 



0-132 (0-00074) 



Table 37 



Statistics of length of brachiophores at their bases (1) and distances between the lateral edges of 

 sockets (w) for n brachial valves of Orthambonites exopunctata sp. nov. (A) and Lenorthis cf. 



proava (Salter) (B) 



A B 



n 6 12 



1 mm (var 1) 1-03(0-111) 0-81(0-034) 



w mm (var w) 2-15 (0-347) I- ^7 (0-09) 



r 0-944 0-727 



a (vara) I'll 1 (0-0848) 1-637 (0-1262) 



Table 38 



Statistics of length of brachial valve (1) and length of adductor scar from umbo (sc) of n specimens 

 of Orthambonites exopunctata sp. nov. (A) and of Lenorthis cf. proava (Salter) (B) 





A 



B 



n 



8 



7 



1 mm (var 1) 



6-i6 (4-389) 



5-46 (2-913) 



sc mm (var sc) 



3-13 (0-899) 



3-06 (0-767) 



r 



0-967 



0-948 



a (var a) 



0-453 (0-00221) 



0-513 (0-0054) 



Subfamily PRODUCTORTHINAE Schuchert & Cooper 1931 



NICOLELLA Reed 1917 



Nicolella cf. actoniae (J. de C. Sowerby) 



(PI. 9, figs. 1-6) 



1839 Orthis actoniae J. de C. Sowerby in Murchison : 639. 

 1963 Nicolella actoniae (Sowerby) Williams : 352. 



Diagnosis. Plano-convex, mucronate Nicolella with a pedicle valve 32% as 

 deep as long and a brachial valve 64% as long as wide, ornamented by 12 to 15 

 angular costae with a wavelength of about i-i mm, 5 mm antero-medially of the 

 dorsal umbo ; costellae rare with 3a arising first, cordate ventral muscle scar extend- 

 ing anteriorly for 34% of the length of the pedicle valve, dorsal adductor scars 

 impressed for 48% of the length of the brachial valve. 



