JURASSIC AND TRIASSIC BRACHIOPODA. 157 



convex, most so posteriorly ; no fold nor sinus, margin-line straight ; beak small, incurved, 

 and truncated by a comparatively large foramen touching the umbo of the opposite valve ; 

 deltidial plates, small but broad and not united in front : hinge-ridges sharply marked, 

 leaving between them and the hinge-line a flattened space. Surface smooth ; length 10, 

 width 9, depth 5 lines. 



05s. — This species is remarkable on account of the flatness of its smaller valve, the 

 whole shell reminding one of Ter. hemispharica, but from which it is at once distin- 

 guished by its larger size and by the absence of the radiating lines observable in the 

 last-named species. 



It has been found by Mr. Walford in the Marlstone or Middle Lias of Aston-le- 

 Walls near Banbury in Northamptonshire ; and it occurs also in the same formation at 

 Adderbury, near Banbury in Oxfordshire. Mr. Innes Griffin has also found the shell 

 in the Am. spina tus zone (Middle Lias) at King's Sutton, near Banbury. I have named it 

 after Mr. Edwin A. Walford, to whom I am indebted for specimens and information with 

 respect to the formations and species that occur in the neighbourhood of Banbury. 



SPECIES WITH LONG LOOPS. 



Genus Waldheimia, King. 



135. Waldheimia quadrifida, Lamarck, sp. Dav., Ool. Mon., p. 28, PI. Ill, figs. 



8—10; Sup., PI. XXI, fig. 20. 



It is singular that almost every palaeontologist in referring to this speeies has adopted 

 Lamarck's name published in 1819. Therefore there are no synonyms to add to it, 

 unless Sowerby's T. cornuta be considered no more than a variety of Lamarck's species. 

 I feel persuaded the more I examine specimens of the two forms, that they merge so 

 gradually one into the other that they are in reality only variations in shape of a single 

 species. This view is shared by Mr. E. Deslongchamps, but, at the same time, he prefers 

 to retain both names for the following reasons : — " La T. quadrifida passe par des degres 

 insensible a Pespece suivante : plusieurs auteurs n'en font qu'une variete de la T. cornuta 

 neanmoins comme la plupart des echantillons ontune forme assez accusee, nous n'hesitons 

 pas a la regarder comme espece, avec les restrictions que nous avons signalies, p. 63. 

 Cest-a-dire, que pour nous, le mot espece signifie simplement groupe de formes se 

 convenant par un certain nombre de points communs et non point l'espece dans toute la 



