VERRUCA. 43 



separated valves from the Red and Coralline Crags, collected by Mr. S. Wood. The 

 moveable opercular valves have not been discovered ; and these are certainly much the 

 most important parts for the diagnosis of the species ; but the other valves are tolerably 

 perfect, and are undistinguishable from recent specimens of V. Stromia ; therefore, I have 

 ventured, with some hesitation, thus to name these specimens. The fossil specimens all 

 belong to the common variety, having its shell longitudinally ribbed, a character not 

 observed in the four other species of the genus. As an aid to collectors in the Crag, I have 

 thought it would be more serviceable to give a drawing (fig. 9 a), from a recent specimen, 

 of all the six valves, separated, but in as nearly as possible their proper relative positions, 

 and likewise of the under side of the fixed scutum and tergum, than to give fac-similes of 

 such valves, in themselves not perfectly characteristic, which have as yet been discovered 

 fossil. 



It should be borne in mind, that of the six valves of which figures are here given, it is 

 just as likely that reversed specimens from the opposite side of the body should be found, 

 as these which represent valves taken from a specimen in which the left-hand scutum and 

 tergum were fixed and formed part of the shell. 



2. Verruca prisca. Tab. II, fig. 10a — 10c. 



Verruca prisca. Bosquet. Monographic des Crustaces fossiles du Terrain Cret. de 

 Limbourg, Tab. 1, fig. 1—6; 1853. 



V. testa IcBvi ; scuti mobilis crista articulari inferior e aliquanto latiore quant 

 superior. 



Shell smooth : moveable scutum, with the lower articular ridge somewhat broader than 

 the upper articular ridge. 



Fossil in Chalk, Norwich, Mus. J. de C. Sowerby : ' Systeme Senonien et Maestrichtien,' Belgium, 

 Mus. Bosquet. 



M. Bosquet has admirably figured and described the several separated valves belonging 

 to this species, and I owe to his great kindness an examination of some of them. In Mr. 

 J. de C Sowerby's collection, also, there is a single specimen (fig, 10a), attached to a 

 Mollusc, with the four valves of the shell united together, but without the two moveable 

 opercular valves ; it cannot be positively asserted that this is the same species with that 

 of M. Bosquet, but such probably is the case. The opercular valves (fig. 103, 10c) are 

 necessarily figured from Belgian specimens. It is the English specimen to which I 

 alluded in the Introduction to my 'Monograph on Fossil Lepadidae.' This species of 

 Verruca is interesting, from being the only known Secondary one, but in itself it is a 



