EXPLANATION OF PLATE XXIV. 
Pic. 
97 BELEMNITES QUINQUESULCATUS. 
/. Lateral aspect. (From the Grey Limestone of White Nab, Scarborough.) 
By erosion at the point the grooves appear. 
v. Ventral aspect, striato-sulcate. 
7. Dorsal aspect, showing the two lateral and one short dorsal groove. 
/", Lateral aspect, with grooved apex, and the phragmocone i sili. 
/”. A specimen, seen dorsally, to show the lateral grooves, and on the phrag- 
mocone the hyperbolic dorsal arcs. 
» . Striation on the conotheca. 
Fragment seen laterally, showing by accidental fracture the interior 
apicial grooves. 
s. Cross section in the alveolar region. 
x, 8’, 8”, #. Cross sections of the sheath. In »s, the interior laminz show 
lateral grooves : in 8”, the terminal grooves are marked by seven tinted 
radial parts: in s”, several grooves appear. 
