PLATE IV. 



Ammonites brocchii, J. Sowerby, Min. Conch., vol. ii, p. 233, 1818, pi. ccii. 



[Brit. Mus. no. 43906.] 



" Specific Characters. — Compressed ; sides hollow, radiated ; inner whorls half 

 concealed ; front circular, with many obtuse ridges ; aperture lunate. 



" Volutions three or four, very round ; twenty radii extending nearly half over 

 them ; the rest of their surface is covered by nearly six times as many obtuse, 

 arched, not very prominent ridges. Were the hollow sides considered as 

 umbilicate, the umbilicus would be conical but would have no defined edge ; the 

 aperture is lunate, inclining to transversely elliptical. Thickness half the diameter. 

 The septa are remarkably numerous, and finely sinuated. 



" From the same friend, and probably from the same place, although of a greyer 

 colour, as A. banhsii, I received the large specimen ; it seems to have been exposed 

 to the weather. 



" The small specimen is from Dundry, by favour Gr. W. Braikenridge, Esq. 



" The name is to commemorate the author of a recent valuable work upon the 

 fossil shells of his own country." 



